Going of by the number of angles (aka the blue dots) I‘m 99% sure the answer would be B. We start off with four angles and it decreases by one with each figure. We have 4,3,2... which leads me to believe that B, with 1 dot, would be the correct answer.
Thinking things through, and looking for all possible outcomes. If you think of all possible outcomes, then you will be prepared and more likely to solve the problem you are solving. This applies to every problem. Also, look at things from different angles.
Answer: changed by molecular oxygen
Explanation:
Biologically induced molecular oxygen (dioxygen, O2) started to accumulate in Earth's atmosphere and changed Earth's atmosphere from a weakly reducing atmosphere to an oxidizing atmosphere.
Answer: B.
Explanation: Cytosis in this context is the taking in, and releasing of various nutrients, proteins, toxins, etc. in and out of the cell. This is facilitated by the plasma membrane because it's our wall that surrounds the cell deciding who goes in and who goes out.