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: Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only do what? Answer: contract
answer:
Skeletal muscles must work in pairs to move bones back and forth at a joint because they can only contract.


question:
Question: Fruit fly and brine shrimp hox genes have evolved independently for how long? Answer: 400 million years
answer:
Fruit fly and brine shrimp hox genes have evolved independently for 400 million years long.


question:
Question: Warm water from the equator mixes with cold water from where? Answer: the poles
answer:

Warm water from the equator mixes with cold water from the poles.