Answer:
A
Explanation:
Today, the atmosphere holds about 21 per cent oxygen. ... When the first simple organisms appeared in the oceans more than 3.5 billion years ago, the atmosphere was mostly nitrogen, hydrogen, water vapor, and carbon dioxide
This can be because of their genetics. The siblings may not have inherited their parents looks, but maybe they inherited their grandparents looks, or even their aunts looks. This is all due to genetics. It's sort of the same thing, when two caucasian parents have an african-american child. That would be because somewhere along the family tree someone was african-american.
Anyways, I hope this helps!
They are rich in hydrogen and helium, they have unlimited supply of hydrogen, they have a strong gravitational pull.
Explanation:
Space where huge size of gaseous and dust cloud is present is called nebula. It is mainly made of hydrogen and helium. Nebula exist in the space which is between the stars and it is call as interstellar space.
Helix nebula is closest nebula which is near the earth. It’s distance from earth is about 700 light years.
Dark nebulae are very dense as well as cold. Nebula can be divided into dark nebula and bright nebula. The gas which is present between the stars is always combine with solid grains cosmic dust.
Answer:
D
Explanation:
An example of osmosis occurs when a sugar solution and water, top, are separated by a semipermeable membrane. The solution's large sugar molecules cannot pass through the membrane into the water. Another good example of osmosis would be dipping a sponge into water, because there is a higher concentration outside, so the water goes in and makes the sponge expand
