Answer:
There are three main classes of parasites that can cause disease in humans: protozoa, helminths, and ectoparasites. Protozoa are microscopic, one-celled organisms that can be free-living or parasitic in nature.
Explanation:
Cell wall because their has to be something protecting it.
Increase and decrease in oestrogen and progesterone.
All living things have DNA within their cells
So Yes
Hope that helped
Answer:
B) A Wolf
Explanation:
A- is wrong because that is multiple organisms
B- correct: it is one organism
C- is wrong because it has no cells
D- is wrong, a heart is an organ which makes up organ systems which makes organisms, but is not an organism itself