<span>Leukocytosis is an increase in the number of white blood cells whereas Leukopenia is an abnormal reduction of white blood cells, giving rise to a significant immune-suppression.</span>
Your answer is D. untestable and open to change
It is the natural/genetic ability of an organism to avoid or repel attack by biotic agents (pests etc.) or to withstand the effects of abiotic agents example (chemicals).
3rd and 4th awnsers are correct