Before there was any life on earth, which gas was absent from the ancient atmosatmosphere? 1)oxygen
2)ammonia
3)nitrogen
4)methane

Answers

Answer 1
Answer: 1) oxygen because without it there cant be any organisms to survive earth so without oxygen there was no life

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20. Which of the following is an example of homeostasis?A human participates in vigorous activity on a hot day and eventually suffers from dehydration.
A human body loses too much heat on a cold day, and hypothermia occurs.
A cactus stores water during wet periods, allowing it to live through dry periods.
A snake rests in the sun on a summer day, and its body temperature eventually becomes too hot for survival.

Answers

Well,

Homeostasis means "maintaining the status quo."  That just means remaining the same.

The first, second, and fourth options, do not represent homeostasis, as something happens to the organism that is not normal.

The third example is an example of homeostasis because the cactus is preparing for the dry period, during which it can maintain the status quo because of its stored water.
A cactus stores water during wet periods, allowing it to live through dry periods.

When rocks form in a discontinuous fashion, they are formed suddenly and their minerals changeTrue or False

Answers

false. they form slowly due to erosion and the minerals stay the same

True. N.L Bowen hypothesized that minerals formed in two different ways. The first is a gradual, continuous fashion with minerals that have very similar chemical components. The second is through a sudden, discontinuous change in the mineral type.

What kind of attitudes should scientists possess? Describe each.

Answers


 Curiousity-A scientist shows interest and pays particular attentions to objects or events. He asks questions and seeks answers.

Honesty-A scientist gives a truthful report of observations. He does not withhold important information just to please himself or others.

Open-Mindedness- A scientist listens to and respects the ideas of others. He accepts criticism and changes his mind if reliable evidence contrdicts his believes.

Skepticism- A scientist bases suggestions and conclusions on evidences. When in doubt, he questions the veracity of a statement in relation to the evidences presented.

Creativity- A scientist can generate new and original ideas.

What is the modern model of an atom

Answers

Electrons are in constant motion around the nucleus, protons and neutrons jiggle within the nucleus

Which type of soil can retain the greatest amount of water?One that has low permeability
One that has low porosity
One that has high permeability
One that has high porosity

Answers

The correct answer would be the soil that has low permeability and low porosity. Soil with high permability and porosity will let liquids run right through it.

Final answer:

One that has high porosity. Soils with high porosity have more pore spaces that can hold and retain water.

Option D is correct

Explanation:

The type of soil that can retain the greatest amount of water is one that has high porosity. Porosity refers to the amount of empty space or pores within the soil. Soils with high porosity have more pore spaces, which can hold and retain water. This is because the water can fill the pores and is not easily drained or lost.

For example, sandy soils have high porosity as they have larger particles and more space between them. This allows water to infiltrate and be held within the soil. On the other hand, soils with low porosity, such as clay, have fewer pores and tend to retain less water.

In contrast, permeability refers to the ability of water to flow through soil. While high permeability can allow water to quickly pass through the soil, it does not necessarily mean the soil can retain a greater amount of water.

Learn more about Soil Types here:

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Organic compounds do NOT contain which of the following?

Answers

Okay... glad you got it but it is good to share in case someone else needs that answer :)
In the 19th century is was assumed that organic compounds could only be produced by plants and animals. These compounds all had carbon and hydrogen in common. Some organic compounds also include O, N, the halogens, S and a few other elements.

Now we know that organic compounds can be synthesized in the laboratory. Simple compounds of carbon and hydrogen include the alkanes and alkenes, for instance, as well as aromatics like benzene. But oxygen is a common element in organic compounds like alcohols, aldehydes, ketones and ethers.

So the bottom line is that all organic compounds contain C and H and some contain O as well, but O is not required to be an organic compound.

========= Follow up ==========

Why are these people saying "yes". It's obvious that there are many organic compounds that don't contain oxygen