A radioactive substance has a half-life of 1.25 million years. What is the age of a rock in which 6.25% of the original radioactive atoms remain? 5 million years old 6.25 million years old 3.75 million years old6 2.5 million years old 1.25 million years old 625 thousand years old
Answer:
The age of the rock is 5 million years
Explanation:
Fraction of radioactive substance remaining = 6.25% = 625/10000 = 1/16
Number of half-lives undergone by the substance to leave behind 1/16 of the original sample
1/16 = (1/2) * (1/2) * (1/2) *(1/2)
Therefore, the substance have decayed 4 times
One half=life = 1.25 million years
Four half-lives = 4 * 1.25 million years = 5 million years
Therefore, the age of the rock is 5 million years
Why must the bonds of these molecules be broken before anything else happens?
Answer:
Synthesis releases energy because the molecules bond to form a stable configuration and therefore give up energy. The bonded molecules have a lower energy level than free molecules and are held in the new bond.
Explanation:
Chemical reactions make and break the chemical bonds between molecules, resulting in new materials as the products of the chemical reaction. Chemical reactions can occur spontaneously or require an outside trigger such as an input of energy. Breaking chemical bonds absorbs energy, while making new bonds releases energy, with the overall chemical reaction being endothermic or exothermic.
Because molecules must link together to establish a stable structure, they lose energy during synthesis. The newly formed bond holds the bonded molecules, which are at a lower energy level than free molecules.
Why the bonds of molecules are broken?Because molecules must link together to establish a stable structure, they lose energy during synthesis. The newly formed bond holds the bonded molecules, which are at a lower energy level than free molecules.
Chemical reactions create and destroy the chemical bonds that hold molecules together, creating new materials as their end product. Chemical reactions can start on their own or need an outside trigger, like an energy input. Chemical reactions can be endothermic or exothermic in that breaking chemical bonds takes energy while creating new ones releases it.
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When Alfred Wegener first noticed that the continents fit together like puzzle pieces, this was
Answer:
- the discovery of the Pangaea Theory.
In 1912 Alfred Wegener (1880-1930) proposed that the continents were once compressed into a single protocontinent which he called Pangaea (meaning "all lands"), and over time they have drifted apart into their current distribution.
The east coast of South America and the west coast of Africa seem to fit together like pieces of a jigsaw puzzle, and Wegener discovered their rock layers “fit” just as clearly. South America and Africa were not the only continents with similar geology. Most all of the other continents fit together too.
Answer:
discovery of the Pangaea Theory.
Explanation:
Perform online research to learn about an invasive species and its new environment. Discuss how the species was introduced to the environment, where it is invasive, what advantages the species has over native species in this environment, and what problems the species poses to the environment.
Answer:
(Answers may vary.)
Farmers brought nutria, a type of large rodents, from South America to North America in the 1990s. They wanted to raise the rodents for their fur. Some of these rodents escaped into the wild and became a major pest in the Gulf Coast and Chesapeake Bay regions. Grasses and shrubs in these regions are vital, because they provide food and shelter for many species. They also help in preventing soil erosion. The nutria are eating up all the grasses and shrubs, which affects the food cycles of these regions. The entire ecosystems are being disrupted.
Moreover, nutria pose a direct threat to humans. These rodents are an effective vector for carrying parasites that can cause disease in humans. They also damage property. The burrows created by nutria can damage dams and building foundations as well as cause erosion near streams and lakes.
Explanation:
the answer from pluto/edmentum
Answer:
The apple snail is a native species of Argentina, Bolivia, Brazil, Paraguay, and Uruguay. Southeast Asia legally imported this alien species to use it as a protein source. Later, this species was brought to places like Hawaii as a source of food.
Like most, if not all, invasive species, the apple snail outcompetes native species for resources. This is because it reproduces rapidly (laying hundreds of eggs every few weeks) and lacks predators. As a result, the snails spread rapidly to aquatic biomes and modify the natural balance of aquatic ecosystems.
Explanation: plato edmentum (answers may vary)
Why does PE = mgh equal PE = Fw h ?
Answer:
Why is potential energy MGH?
Potential energy is energy an object has because of its position relative to some other object. ... For the gravitational force the formula is P.E. = mgh, where m is the mass in kilograms, g is the acceleration due to gravity (9.8 m / s2 at the surface of the earth) and h is the height in meters.
Explanation:
Yes Yes Yes Yes Yes Yes
Evan's nightly chores include washing dishes. His mother cooks everything she prepares a bit too long. Because of this, Evan spends a lot of sweat, effort, and time washing dishes. He sees a commercial on television that claims a new dishwashing detergent, called Brand X, cuts through grease better than its competitor, called Brand Y. They back up their claim with testimonials from people who say they've used this new detergent.
What is a possible testable question (in correct format) that Evan might ask for in this scenario?
IV:
DV:
Answer:
product X and Y need to be in a controlled test to make see how they do undergoing the same things.
hope this helps :)
Explanation:
3. Draw a circle on a flat surface. Look at it from the side. What do
you think you'll see?
circle
egg shape
ellipse
bean shape
4. Which of the following
would you be able to use to make a specific ellipse?
lengths of major and minor axes
positions of the two foci
positions of the two foci and the center
the circumference and center
can you pls help me ??
Compare and contrast a few aspects of animal and plant cells. You can focus on intra- and extracellular structures they share or don't share, but also be sure to describe processes they both utilize or don't both utilize. Some things to consider: How they obtain 'food' (what is their organic carbon source?) What structures do they share that prokaryotes lack? What do they share that all living cells also share? Do they use CO2, and/or O2 in any processes?
Answer and explanation:
Although they share some similarities because they are both eukaryotes, plant cells and animal cells are quite different from each other, which is logical since they have distinct lives.
For example, animal cells and plant cells both have a cell membrane, but only the plant cells have a cell wall - which is thick and resistant, and this makes sense because they are more exposed to mechanical and osmotic stress.
Since animals can move towards sources of water but plants cannot, there's also a way in which plants store water in the cells: vacuoles. Animal cells have vacuoles as well although they are much smaller than the single huge vacuole that plant cells have.
All living organisms need the energy to sustain different cellular processes. The organelle in charge of the chemical reactions behind the obtention of energy is the mitochondria, which is present in all cells, but the mitochondrion needs a specific substrate: glucose. Glucose is obtained in diverse ways: animals move and find food that contains glucose in it, while plants produce their own glucose with a specific process called photosynthesis, for which they need an organelle called chloroplast, which animals do not have. In order to transform the glucose into energy, the mitochondria end up generating CO2, which animals expel from their bodies by exhaling. This CO2, now in the air, is used by plant cells as a substrate in photosynthesis (which needs sunlight as well) to produce glucose and also O2, that will be inhaled by animals and used by their tissues.
All living organisms have one thing in common: they possess DNA. DNA contains all of the genetic information of an organism, and it is present in almost every cell of that organism -if it happens to be a multicellular being-. While prokaryotes have their DNA condensed into a single circular chromosome, eukaryotes like plants and animals, have their DNA form many linear chromosomes (quantity varies according to the species) and these chromosomes are inside a very specialized organelle: the nucleus, which prokaryotes do not have.
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Answer:
The vaccine that protect humans from the h1n1 virus is called Panvax vaccine or swine Explanation:They are inactivated H1N1 virus vaccines used for immunization of individuals 6 months of age and older against influenza disease caused by H1N1 2009 virus.
Compare fossil fuels and
biomass as energy resources.
Answer:
Compare fossil fuels and biomass as energy resources. Both fossil fuels and biomass come from organic matter, are burned to generate energy, and cause air pollution when used. Biomass is renewable, whereas fossil fuels are nonrenewable.
Explanation:
The energy available to consumers determined by subtracting the energy used by plants from the total energy
transformed by the process of photosynthesis.
А
et your pas
Primary productivity
B
Gross primary productivity
С
Net primary productivity
D
Cellular respiration
Answer:
C. Net Primary productivity
Explanation:
In an the food chain of an ecosystem, energy is constantly being gained and most. Producers are the set of organisms that start the energy cycle via the process of photosynthesis. The gross primary productivity (GPP) is the amount of energy that the producer is able to capture from sunlight during photosynthesis.
The rate at which that captured energy is used to produce chemical organic compounds, which served as food, is called the primary productivity of the producer. However, the NET PRIMARY PRODUCTIVITY (NPP) is the energy available to consumers, which is determined by subtracting the energy used by plants via metabolism, from the total energy transformed by the process of photosynthesis. Hence, mathematically, NPP = GPP - R
Where, R = energy lost via respiration.
guys please help
Question 11 Part A)
Make sure to sure me your work.
Answer:
95%
Explanation:
190 is 95% of 200.
The comparison of input versus output is also 95%
All human body cells contain 46 chromosomes. However, sperm cells in men and egg cells in women have only 23 chromosomes. This is due to meiosis. How does meiosis accomplish the reduction in chromosomal number?
Answer:
Two cell divisions after DNA replication
Explanation:
After the DNA is replicated, the cell undergoes two rounds of meiosis to produce 4 cells, each wIth 23 chromosomes. This is how the cell goes from a diploid to a haploid state.
The speed at which waves approach the shore depends on the shoreline features and the depth of the sea floor. When a wave reaches the shore, it releases a burst of energy that generates a current which runs parallel to the shoreline. What is this current called?
Answer:
Longshore current.
Explanation:
A wave is a disturbance which travels through a material medium without any permanent displacement of the particles of the medium. During the propagation of a wave, energy is transmitted from one point to another since waves flow with energy. The higher its speed of propagation, the higher the energy of the wave.
The energy released by the wave at shore produces a current which is referred to as a longshore current.
Answer:
It would be Longshore Current
Explanation:
Hope it helps :)
What process best explains how a nerve cell and a muscle cell can both
develop from the same fertilized egg?
O A. differentiation
O B. natural selection
O C. selective breeding
O D. genetic engineering
Need ASAP!
Answer:
Im pretty sure its A.
Explanation:
=just took the teskst
Answer: The correct answer is A. differentiation
Explanation: Confirmed correct.
The passage of genetic instructions from one generation to the next is known as what?
Answer:
heredity
Explanation:
Answer: heredity because it is
State two features of diffusion that do not apply to active transport
Information about which of the following would be most pertinent to a small organic farm that solely relies on manual labor to till, plant,
water, and harvest crops?
dehydration and heat exposure precautions
heavy equipment training and maintenance
drip irrigation installation and maintenance
hazardous chemicals storage precautions
Answer:A
Explanation:
If i had to guess its A because its the only one that doesn't require equipment, since the question said it was a small organic farm that only practiced Manuel labor.
Answer:
dehydration and heat exposure precautions
Which organelle provides support for the cell and may also help the cell move?
Cell Membrane
Cytoplasm
Cytoskeleton
Ribosome
Two students completed an experiment to determine if pesticide use at local farms was causing fish kills in a local pond. The steps of the experiment are listed below. Select one location to collect water samples in the pond. Collect a 5-mL water sample at 8 am for two days. Measure the amount of pesticide present in each sample using the same measurement tools. After analyzing their data, the students conclude that pesticide runoff from farms is not causing the fish to die in the pond. Which of these statements best describes why their conclusion is not reliable? The pesticide measurements were the dependent variable. The samples were collected at different times. The samples were only collected for two days. The time of sample collection was not an independent variable.
Answer:
The pesticide measurements were the dependent variable
Explanation:
According to this question, an experiment to determine if pesticide used at local farms was causing fish kills in a local pond was conducted by two students. They followed the following steps:
- Select one location to collect water samples in the pond.
- Collect a 5-mL water sample at 8 am for two days.
- Measure the amount of pesticide present in each sample using the same measurement tools
However, after analyzing the data, they concluded that "runoff from farms is not causing the fish to die in the pond". The students' conclusion is not reliable because THE PESTICIDE MEASUREMENTS WERE THE DEPENDENT VARIABLE.
Note that, the dependent variable in an experiment is the measured variable while the independent variable is the manipulated variable. In this case, the students ought to measure the death RATE OF FISH KILLS as the dependent variable instead. The PESTICIDE is the independent variable of the experiment not dependent variable. This was the reason for the unreliability of the conclusion.
Milk sugar is a good source of;
A)galactose
B)glucose
C)fructose
A herniated disc is also sometimes referred to as:
A. Ruptured disc
B. Bulging disc
C. Slipped disc
D. All of the above
Explanation:
If the spinal column tears open and the discs protrude outward, they can press on, or “pinch,” nearby spinal nerves. This is known as a ruptured, herniated, or slipped disc.
What type of bond is being formed in this polymerization reaction to link two amino acids together?
When an atom loses an electron, it becomes a?
Identify minerals extracted in Haiti
and describe what is done with
them.
Answer: Haiti is mainly know for their minerals! the main minerals extracted are: cooper, silver, and GOLD. Haiti has many many gold farms, markets, etc. HOWEVER this is a very poor area, as people here live off of only about 2 dollars per day. They could take this wealth and put it towards the people, roads, and construction, as they had an earthquake that killed many many people, and destroyed much. If you mean what they do with gold, they take the gold from farms, and mine it underground. They then sell it for money as this is a poor area as said before!
Explanation: I hope this helps! please let me know and have a great night! :)
A form of simple cittusion is Osmosis. In which direction will water flow in the process of Osmosis?
A. Water will flow from low concentration to higher concentration
B. Water will flow with the solutes, against the concentration gradient
C. Water will flow towards the solutes (.e. toward the higher salt concentration)
D. Water will flow away from the solutes, with the concentration gradient
Answer: D
Explanation:
osmosis, water always moves from an area of higher water concentration to one of lower concentration.
A population distribution shows _______.
a.the distribution of age groups within a population
b.the amount of organisms in a unit area
c.the total number of organisms in a population
d.where and in what arrangement organisms are located
Answer:
D
Explanation:
Think about the definition of “distribution “.
If a person combat the disease without a vaccine introduced to his body,such immunity is known as
natural active immunity
natural passive immunity
Artificial active immunity
artificial passive immunity
Answer:
natural active immunity will be the answer
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A team of engineers is designing a new ship. The engineers first build several models of the ship. Explain in your own words why the models could help the engineers
Answer:
The model could help the engineers by giving they a prototype to build off of so they have an idea of what they ship looks like, and if the test it, they could troubleshoot and see the errors/successes of the model.
Explanation:
The engineers first build several models of the ship as the model could help the engineers by providing them a prototype to build of so that they have an idea of what or how the ship will looks like, and if they test it, they could troubleshoot and see the errors or successes of the model of the ship.
What are the fields in which science is applied?Science has the factual based knowledge and it has about the Nature as well as the natural world that has created on the basis of observations and the experiments. It has the study of the experiments and observations and it has totally depend upon the scientific result that has obtained after the scientific experiments.
There are several fields in which science has been applied and these field are healthcare, telemarketing, environmental engineering, banking, government regulation, space, biochemistry, physics, chemistry, biochemistry and astronomy, engineering.
Therefore, The engineers first build several models of the ship as the model could help the engineers by providing them a prototype to build of so that they have an idea of what or how the ship will looks like, and if they test it, they could troubleshoot and see the errors or successes of the model of the ship.
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