Answer: Definition
Explanation: In science, the word 'theory' refers to the way in which people interpret facts. A scientific theory is the framework for observations and facts. Theories may change, the way in which they are interpreted may change, but the facts remain the same.
First, he should measure how long it takes for the liquid to become clear if X and Y are mixed together. Then, he should measure how long it takes if he also adds substance A to X and Y. He will find out if substance A is a catalyst.
Answer:
During cellular respiration glucose is broken down in the presence of oxygen to produce carbon dioxide and water.
Explanation:
If you are friend smoke you are increased more likely to start smoking then a child of non smoker
