instruction:
Given a scientific question, generate a correct answer to it.
question:
What is at the surface of a cell, arranged in similar bilayer?
answer:
phospholipids

question:
Through what part do exocrine glands discharge their contents?
answer:
tubular ducts

question:
The rate at which the body uses food energy to sustain life and to do different activities is called the what?
answer:
metabolic rate