Answer:
Oxygen levels are generally thought to have increased dramatically about 2.3 billion years ago. Photosynthesis by ancient bacteria may have produced oxygen before this time. ... In addition, early plants and algae began to release oxygen at a faster rate. Oxygen levels then showed a dramatic increase.
The answer is A. a light wave
C and D both need water as a medium and sound needs air to vibrate in order to travel. light, on the other hand, does not need a medium
This solution will work, because the amount of rocks and the size of the rocks also depend on how much farther you will move, although once you start to build up a little bit of inertia it will become easier.
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Answer: It is D. As we know, DNA stores information. Well, DNA is a nucleic acid, so the answer would be nucleic acids. For the second part, DNA encodes the information the cell needs to make proteins. So, the answer for the second part is protein.
