Answer: Sperm cells are recognised as foreign cells by the immune system and requires blood testis barrier to prevent antibody formation.
Explanation:
Shortly after birth, the immune system of an individual starts to recognize the surface antigens of its body cells as 'self' and avoids forming an antibody against it. Spermatozoa (sperm cells) are formed at puberty, between the age of 10 and 14. Hence, the body immune system will recognise the antigen on the sperm cells as 'non-self' and stimulate antibodies against it. This is prevented by the blood testis barrier.
The blood testis barrier which are formed from the Sertoli cells at the seminiferous tubules helps in the isolation of the sperm cells and protects it from immune surveillance. This barrier also prevents sperm cells from coming in contact with blood.
If we look at ths other options Chloroplast and Cell Wall are both needed for a plant to survive and function. So we automatically know that it's going to be there so those aren't an option. We know that both animal and plant cells have a vacuole but plant cells have larger ones so we know that's not an answer. Leaving us with the only other possible answer left, Centrioles.
