Question

When applying the process of science which of theseis tested 1.a question, 2.an observation, 3.a conclusion, 4.a prediction

Answer 1

4. a prediction

Explanation:

According to the scientific method, an experiment is conducted to test a prediction/hypothesis stemming from the previous question.

Answer 2

A conclusion ... usually called a "theory" ... is tested. (3)

One great way to test a conclusion is to follow up on its predictions, and see how they turn out.