The bird was frightened by the human as a defense mechanism it knows to fly away for safety.
The answer should be <span>early 1800's </span>
Answer:
B
Explanation:
In a command Economy, 1 is right. 3 and 4 are plain Rubbish.
Cell-mediated immunity is directed primarily microbes that survive in phagocytes and microbes that infect non-phagocytic cells. It is most effective in destroying virus-infected cells, intracellular bacteria, and cancers. It also plays a major role in delayed transplant rejection.
