Which one of the following is categorised as a parasite in true sense?
The female Anopheles bites and sucks blood from humans
Human foetus developing inside the uterus draws nourishment from the mother
Head louse living on the human scalp as well as laying eggs on human hair
The cuckoo (Koel) lays its eggs in crow's nest
Head louse living on the human scalp as well as laying eggs on human hair is a parasite in true sense. Female mosquito is not considered as a parasite, through it needs human blood for reproduction. Koel that lays in crow's nest is just a brood parasite.