Which of the following is an example of symbiosisa. Bacteria on the legs of fliesb. Lichenc. Taenia saginata in the gut of mand. Pediculus humanus on the head of human

The example of symbiosis from the options provided is b. Lichen.

Here's why:

Symbiosis is a close and long-term biological interaction between two different biological organisms. It can be mutualistic (both organisms benefit), commensalistic (one organism benefits, the other is unaffected), or parasitic (one organism benefits, the other is harmed).

a. Bacteria on the legs of flies - This is not necessarily symbiotic as it doesn't always benefit both organisms. The bacteria may benefit from transportation, but it doesn't necessarily benefit the fly.

b. Lichen - This is a classic example of symbiosis. Lichen is made up of a fungus and an alga or cyanobacterium. The fungus benefits from the nutrients produced by the alga or cyanobacterium through photosynthesis, and the alga or cyanobacterium benefits from the protection and structure provided by the fungus. This is a mutualistic relationship.

c. Taenia saginata in the gut of man - This is a parasitic relationship, not symbiotic. The Taenia saginata (a tapeworm) benefits by feeding off the host (man), while the host is harmed by the tapeworm's presence.

d. Pediculus humanus on the head of human - This is also a parasitic relationship. The Pediculus humanus (a louse) benefits by feeding off the host (human), while the host is harmed by the louse's presence.