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:
S phase.
Explanation:
During this phase, the DNA within the cell is also copied during this process.
Sorry, but I don't want to do your essay. I wish you luck tho :>
Answer: The correct answer is- B) Ecosystem.
Ecosystem can be described as a group of living organisms present in a particular area that are interacting with each other as well as the non living components of that environment.
In other words, it is the interaction between biotic ( living such as plants and animals) and abiotic ( non living such as temperature, air, water) components of an environment.
Example- Pond ecosystem, lake ecosystem.