TASK DEFINITION: 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.
PROBLEM: Question: Ultimately, most life forms get their energy from this? Answer: sun

SOLUTION: Ultimately, most life forms get their energy from the sun.

PROBLEM: Question: Carbon dioxide does not rise like other gases because it has a density greater than what? Answer: air

SOLUTION: Carbon dioxide does not rise like other gases because it has a density greater than air.

PROBLEM: Question: Memory t cells are long-lived and can even persist for how long? Answer: lifetime

SOLUTION:
Memory t cells are long-lived and can even persist for lifetime long.