261: Which one of the following is the best description of the term 'ecosystem'?
(a) A community of organisms interacting with one another.
(b) That part of the Earth which is inhabited by living organisms.
(c) A community of organisms together with the environment in which they live
(d) The flora and fauna of a geographical area
262: Mycorrhiza is a symbiotic association between
(a) Bacteria and roots of higher plants
(b) Algae and roofs of orchids
(c) Fungi and roots of higher plants
(d) Protozoa and roots of higher plants
263: In the eye donation, which part of the eye is transplanted from the donor ?
(a) Cornea
(b) Lens
(c) Retina
(d) The whole eye
264: Gerontology is the study of:
(a) Process of ageing
(b) Growth of cells
(c) Birds
(d) Vegetables
265: Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use ?
(a) Aspartame is several times sweeter than table "sugar, hence food items made with small quantities of aspartame yield fewer calorieson oxidation
(b) When aspartame is used in food processing, the sweet taste remains, but it 'beccmes resistant to oxida- tion
(c) Aspartame is as sweet as sugar, but after ingestion into the body, it is converted into metabolites that yield no calories
(d) Aspartame is as sweet as table sugar, but unlike table sugar, it is not readily oxidized in human body due to lack of requisite enzymes