Answer:
All viruses are obligate parasites; that is, they lack metabolic machinery of their own to generate energy or to synthesize proteins, so they depend on host cells to carry out these vital functions.
Explanation:
leukocyte cells as neutrophils has the property of phagocytosis. and lymphocytes cells such as B & T lymphocytes in which b-lymphocytes produces antibodies against particular antigen and T Lymphocytes destroy infected cells.
Answer:
D. It is a random guess about how something happened.
Explanation:
In everyday life, a theory is a hunch or a guess about how something happens (in the scientific method, we might call it a <em>hypothesis</em>).
A is <em>wrong</em>. It doesn’t necessarily explain how nature works, because it hasn’t been tested by experimental testing and observation.
B and C are <em>wrong</em>. They are features of the <em>scientific method</em>.
