Which of the following is an example of the symbiotic relationship known as mutualism?

a. saprophytic mycobacterium of the ear
b. e. coli within the large intestine
c. a tapeworm in the gastrointestinal tract of a human
d. corynebacterium on the surface of the eye

E. coli within the large intestine. (Ans. B)

Explanation:

Mutualism is ecological interaction and defined as a relationship in which both species get benefits. E. coli forms a symbiotic relationship (mutualism) with its host organism.

E. coli is minor microflora found in humans which helps in the absorption of vitamin K and some other important vitamins for the colon of the human body. E. coli get benefits from its host in the form of protection, proper nutrients for proper function and growth.

Mutualism involves the exchange of shelter, nutrients, protection and transportation.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.