Ans: (a)
337. When a cell neither shrinks nor swells when kept in a fluid, then the fluid in the cell in relation to ambient fluid is called:
     [NDA 1990]
     (a) Hypertonic
     (b) Hypotonic
     (c) Isotonic
     (d) Hyalotonic
Ans: (c)
338. The study of the relation of animals and plants to their surroundings is called: [Intelligence Bureau 1994]
     (a) Ecology
     (b) Ethnology
     (c) Genealogy
     (d) Iconology
Ans: (a)
339. Ants are always seen moving in a line one after another. They trace the path because of the secretion of chemicals
     (a) detectors
     (b) sex hormones
     (c) pheromones
     (d) None of the above
Ans: (c)
340. The maximum fixation of solar energy is done by: [Intelligence Bureau 1994]
     (a) bacteria
     (b) protozoa
     (c) fungi
     (d) green plants
Ans: (d)
341. Which of the following animals resembles most to human beings in terms of physical and mental capabilities?
     (a) Langur
     (b) Rhesusmonkey
     (c) Gorilla
     (d) Chimpanzee
Ans: (d)
342. Which of the following have not undergone much .of a change during the process of evolution over millions of years?
     [CDS 1994]
     1) Crocodile
     2) Cockroach
     3) Horse
     (a) 1 and 2
     (b) 2 and 3
     (c) 1 and 3
     (d) 1, 2 and 3
Ans: (a)
343. Nitrogen fixation is done by : [IFS 1990]
     (a) red algae