instruction:
In this task, you are given a question and an answer, you would be asked to create the sentence based on the Question-Answer provided. It should be contained within the Question-Answer provided.
question:
Question: What happens when forces of evolution work over a long period of time? Answer: macroevolution
answer:
Macroevolution happens when forces of evolution work over a long period of time.

question:
Question: What is the name of the location in which a stream or river starts? Answer: source
answer:
Source is the name of the location in which a stream or river starts.

question:
Question: Which rule is a result of trends in energies and is useful in explaining why atoms form the ions that they do? Answer: octet rule
answer:
The octet rule is a result of trends in energies and is useful in explaining why atoms form the ions that they do.