I believe the answer would be how it is performed.
T cells attack antigens on foreign substances and B cells produce antibodies.
A. a high fat diet
you have to watch what you eat.
Answer:

Explanation:
We need to write the value of
. It is a well known identity of algebra.

Here,
b and c are any number.
We know that,
b² = b×b
bc = b × c
Hence, this is the required solution.
Answer:
They are made by living things.
Explanation:
humans are living things, thus do not make vitamins.