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:
1 quarter of a million especially young men who have dependents to go into the forestry and flood prevention work.
Answer:
the defention of environment is the surroundings or conditions in which a person, animal, or plant lives or operates
Explanation:
because the natural world, as a whole or in a particular geographical area, especially as affected by human activity.
Answer:
Because the biodiversity decreases.
Explanation:
An ecosystem is richer when it has a higher biodiversity, remember that each living thing has an specific role in the food web. When in an ecosystem this web is bigger, increases the probability of sustain a living thing. For example, in the sea, if there is a fish, this is going to be more probabilities of survive if this fish can eat different plants or other fish. But if in the ecosystem there are not a variety of them, it probability to survive is less if one of it food desapear.
