TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Carbon 14 isotope of carbon is typically used to date ancient items.

SOLUTION: What isotope of carbon is typically used to date ancient items?

PROBLEM: Like skeletal muscle, cardiac muscle is striated.

SOLUTION: Like skeletal muscle, cardiac muscle is what?

PROBLEM: Most of the energy used by living things comes either directly or indirectly from the sun.

SOLUTION:
Most of the energy used by living things comes either directly or indirectly from what?