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. hope this helps :)
Answer:The answer is A
Explanation:I have had the question before
I assume that you would be evaluating the whole animal if it’s a a physical examination so B
Answer: The effects of which are devastating to human life, flora and fauna, which depend on these resources for their survival. Contamination of water causes disruptions of food chains and destruction of ecosystems. A deadly by-product of this water pollution is the spread of water-borne diseases such as cholera, typhoid etc.
Explanation:
