Hello there! :D
Yes, biology! Love getting some cool science questions. :)
Let's start by reviewing the context of the question:
We know that all living things grow, and that multicellular and unicellular organisms do so in different ways.
How do multicellular organisms grow?
We go through a process called Mitosis for Somatic (body cells), and Meiosis for Gametes (ovum and sperm). We do this to grow and to procreate. Humans are multicellular, so is your dog, Barry B. Benson, and all the beautiful flowers and trees that you see outside in the spring time.
Second question, ya like jazz? Nah, haha. How do unicellular organisms grow?
They grow through expansion! Their only cell grows until it reaches maturity and it begins to split (divide) to form more unicellular organisms. An example of a unicellular organism that does this is yeast, which is in most bread.
Now that we have our context, we can answer this question. What is the topic we talked about this most in covering context? Cell divison!
The answer choice that covers this topic the best is answer "A".
I hope this helps you and you have a wonderful day,
Kai xx