Why were there no living inhabitants on earth for the first billion years?

Answers

Answer 1

There was no life on Earth for the first billion years because the atmosphere was not suitable for life. Earth's first atmosphere had lots of water vapor but had almost no oxygen. Later, frequent volcanic eruptions put several different gases into the air.


Related Questions

List any organisms that lack tissues

Answers

Answer: Of all the branches of complex animals, sponges are the only group lacking TRUE TISSUE.

Explanation:

fossils of marine organisms hi in the Andes mountains lead Darwin to conclude that???

Answers

Answer:

its C

Explanation:

the answer is c, great geologic change can happen over long periods of time

which era was the paleozoic era

Answers

Answer:

541 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history.

source- Britannica

Explanation:

Which of the following is lost to the environment as heat so that it cannot be continually recycled?
Group of answer choices

oxygen

nitrogen

phosphorous

energy

Answers

Answer:

Energy

Explanation:

Many chemical reactions release energy in the form of heat, light, or sound. These are exothermic reactions. Exothermic reactions may occur spontaneously and result in higher randomness or entropy (ΔS > 0) of the system. They are denoted by a negative heat flow (heat is lost to the surroundings) and decrease in enthalpy (ΔH < 0). In the lab, exothermic reactions produce heat or may even be explosive.

Explain why a topographic map has a key.

Answers


Topographic maps represent the locations of geographical features, such as hills and valleys. Topographic maps use contour lines to show different elevations on a map. A contour line is a type of isoline; in this case, a line of equal elevation. If you walk along a contour line you will not go uphill or downhill.

Topographic maps represent the locations of geographical features, such as hills and valleys.

What do you mean by topographic maps?

Topographic maps use contour lines to show different elevations on a map. A contour line is a type of isoline; in this case, a line of equal elevation.

In modern mapping, a topographic map or topographic sheet is a type of map characterized by large-scale detail and quantitative representation of relief features, usually using contour lines.

A topographic map is a detailed and accurate illustration of man-made and natural features on the ground such as roads, railways, power transmission lines, contours, elevations, rivers, lakes.

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Research on animals is not relevant to people because animals are different from people.

A. True
B. False

Answers

The answer is FALSE.
A.) True


The pain , the suffering, and deaths of animals are not worth the possible human benefits.

Some cells have structures called chloroplasts, which contain the green pigment chlorophyll.

a) Explain the role of chloroplasts in these cells.

b) Name two things from the environment that chloroplasts must have to perform this
role.

Answers

Answer:

Chloroplasts convert light energy to chemical energy to supply food to the plant through a process called photosynthesis

Water and Sunlight

What is true about a trophic level in an ecosystem?
Select all that apply
The amount of energy flowing into secondary consumers must equal the
amount that flows into primary consumers.
The ecosystem is an isolated system.
The ecosystem is an open system
The amount of energy flowing into the secondary consumers is less than
the amount that flows into the primary consumers.

HHEELLPPPHHH

Answers

The amount of energy flowing into secondary consumers is less than the ambit that flows into the primary consumers, and the ecosystem is an open system are true... I think

Explain why index fossils are important.

Answers

Answer:

Index fossils are used by geologists and palaeontologists as significant aids to determine the correlation and age of rock formations. Geologists use large fossils or macrofossils and microscopic fossils or microfossils as indices to define and identify geologic periods.

Explanation:

Why is it important that the seedling’s true leaves grow quickly?HURRY IM BEING TIMED

to help disperse seeds to areas where they can grow
to shield the seedling from too much water or rain
to protect the seedling from receiving too much sunlight
to make food for the seedling’s continued growth

Answers

Answer:

The correct answer is - to make food for the seedling’s continued growth.

Explanation:

The true leaves that emerge from the seedlings are the leaves that are capable of performing photosynthesis and start generating food and energy. These support the plant for the rest of its life in terms of food and energy.

Seedlings grow from the soil, two leaves in beginning called cotyledons that are not the true leaves and not able to perform photosynthesis and generate their food for the seedling’s continued growth.

All of the following are used by taxonomists to create evolutionary links between species EXCEPT
Select one:
a. analogous structures
b. the fossil record
c. molecular data
d. vestigial structures

Answers

A Analogous structures

The fossil record, molecular data and vestigial structure would help taxonomists to create evolutionary links between species except analogous structures.

What do you mean by fossil record?"A fossil record is a group of fossils which has been analyzed and arranged chronologically and in taxonomic order."What is molecular data?"Molecules such as sequence of DNA used in studies of intra-specific variation and studies of similarity among species."What is vestigial structure?"Structures that have no apparent function and appear to be residual parts from a past ancestor are called vestigial structures."What do you mean by taxonomists?"Taxonomists are professionals who specialize in classifying and sorting information based on similar characteristics and patterns."What are analogous structures?The structure of different species performing similar function but are from different origin (do not have common ancestor).

The fossil record, molecular data and vestigial structure all would help taxonomists to find evolutionary links between species where through  analogous structures no links would be created.

Hence, the correct option is a. analogous structures.

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Hormones for glucoregulation are secreted by a gland called??

HELP ASAP PLZ

Answers

Answer:

Pancreas ( ilets of Langerhans)

Explanation:

Match the position to the closest estimation of its current career outlook.
agricultural engineer
landscape architect
agricultural managers
loss of more than 5 percent
:: growth of more than 15 percent
growth of less than 10 percent

Answers

Answer:

can you rephrase your question im not understaind it, if you can i can answer it for you

Explanation:

The process that moves bits of rock or soli from one place to another Mark only one oval

Answers

Answer:

erosion

Explanation:

hope this helps

:)))

hello please help i’ll give brainliest

Answers

Atmosphere is the correct answer!

Answer: Atmosphere

Explanation: It isthe envelope of gases surrounding the earth and protect it

Melting ice sheets increase the volume of water in the oceans and reduce the salinity of water. How would this affect:

a) sea animals in polar regions?
b) coastal areas already at sea level?

Answers

Answer:your answer is B

Explanation:

In the polar regions if the water goes onto shore it would freeze adding to the icy land and giving sea animals an advantage as all the sea animals would be at the to of the sea level giving a better attack on prey. as in Coastal area it would flood the area causing and flood.

HELP BRO PLEASE



What is a major threat facing Intertidal zone ecosystems?

the mysterious disappearance of phytoplankton

exceptionally high or low tides

habitat destruction caused by hurricanes

pollution caused by human activities

Answers

Answer:

I believe it's the second one.

The crust is the thickest layer of the earth true or false​

Answers

Answer:

The crust is not the thickest layer of earth

:)

Answer:

No

Explanation:

The core is the thickest layer of the earth! Which the crust is relatively thin compared to the other layers

50 points welp
Mums are plants that bloom in the fall.

Which statement describes the photoperiodism of mums?

They bloom when the days are longer.
They bloom when the nights are longer.
They bloom when the temperatures are warmer.
They bloom when the temperatures are colder.

Answers

Answer:

They bloom when the nights are longer.

Answer:

2. They bloom when the nights are longer

Explanation:

Photoperiodism means the reaction to length of a day or night cycle, since fall is the beginning of shorter days and longer nights, it is only reasonable that the answer is that They bloom when the nights are longer.

if environmental conditions change over time it’s most likely a population of organisms in the environment will survive if...

Answers

the answer is “there is genetic variation within the population”

all plant bodies(root,stem and leaf) are externally covered by epidermis but why woody plant is covered by barks​

Answers

Answer:

Bark comprises all the tissues surrounding the xylem in woody plants. Broadly, bark includes an inner and mostly living region and an outer, dead one. Of all plant structures, bark has the most complex anatomical structure and ontogenetic origin involving two (and often three) different meristems.

As to why, the bark adds layers to the inside ring of the vascular cambium, the outside is pushed outward. The cells die off, and the fibrous matrix of cellulose and lignin molecules remain. This hard structure forms the bark, and protects the tree or plant from many forms of damage.

What would happen to zygote if the egg and sprem cells weren't formed with the correct number of chromosomes?

Answers

Answer:

A zygote can end up with one fewer chromosome than normal because one of the fertilizing gametes was missing a chromosome. This deletion, called nondisjunction, happened while the gamete was forming.

Explanation:

GIVING AWAY 14 POINTS PLEASE HELP ME ON THIS QUESTION ASAP!!!!

Answers

Answer: i think its B or C

Answer: B

Explanation: Hope this help :D

Which of the following groups of people be the least affected by air pollution?

Answers

Answer:

The group which would be the least affected by air pollution are C. teenagers. This is because their respiratory systems have already been established and are quite strong because they are still young and healthy. People with asthma already have troubles breathing, so obviously air pollution is going to be a problem.

Explanation:

Hope it helps :)

Your immune systems main function is?

A. Takes in oxygen and removes carbon dioxide and water

B. Allows organisms to reproduce preventing their species from becoming extinct

C. Fights off foreign invader

D. Transport materials to and from cells

Answers

The answer is C. Fights off foreign invader
C fight off foreign invader, the immune systems is like to fight off different sickness

How is efficiency related to systems?

Answers

The efficiency indicates the manner in which the inputs are used by the system. Being efficient means the system uses inputs in a `right' way. If the input-output ratio is adverse, we say that the system is inefficient though it produces the desired output.


Can you please help me with this...

Answers

Answer:

A. Asexual

Explanation:

I majored in Biology

The nervous system is the major ______ system of the body.
A. output
B. control
C. transport
D. protective

Answers

Answer:

B. Control

Explanation:

control system of the body

Carbon that is stored for millions of years is found in the form of

Answers

Answer: They can be found in Fossil Fuels

Explanation:

When animals die, they release carbon which goes into the ground and when it's stored for so long it turns into fossil fuels :)

Answer:

most is stored in rocks the rest is ocean plants soil atmosphere and fossil fuels.

Explanation:

The atmosphere of Earth is made up of nitrogen, oxygen, water vapor, carbon dioxide, methane, nitrous
oxide, and ozone. Of these, 99% of the atmosphere is composed of:

Answers

Answer:

Nitrogen and oxygen account for 99 percent of the gases in dry air,

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