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: When substances pass through the cell membrane without needing any energy what is it called? Answer: passive transport

SOLUTION: When substances pass through the cell membrane without needing any energy, it is called passive transport.

PROBLEM: Question: Producing light without heat is called what? Answer: luminescence

SOLUTION: Producing light without heat is called luminescence.

PROBLEM: Question: What is the matter through which sound waves travel? Answer: medium

SOLUTION:
Medium is the matter through which sound waves travel.