An ecosystem, such as an aquarium, is self-sustaining if it involves the interaction between organisms, a flow of energy, and the presence of

1) equal numbers of plants and animals
2) more animals than plants
3) materials cycles
4) pioneer organisms

Anal cerci are present in
1. Only in female cockroach
2. Only in male ascaris
3. Only in male cockroach
4. In both male and female cockroach

Origin and evolution of algae is best displayed by
1) Blue green algae
2) Green algae
3) Red algae
4) Brown algae

Assuming complete ionisation, the pH of 0.1M HCl is 1. The molarity of H₂SO₄ with the same pH is:

1) 0.1
2) 0.05
3) 0.2
4) 2.0

A source of sound S emitting waves of frequency 100 Hz and an observer O are located at some distance from each other. The source is moving with a speed of 19.4 ms^-1 at an angle of 60° with the source observer line as shown in the figure. The observer is at rest. The apparent frequency observed by the observer (velocity of sound in air 330 ms^-1)is :-


1) 97 Hz
2) 100 Hz
3) 103 Hz
4) 106 Hz

 1. Bryophytes play an important role in plant succession on bare rocks or soil.
2. The plant body of bryophytes is more differentiated than that of algae. Regarding 1 and 2 :

1) 1 is incorrect but 2 is correct
2 ) Both are incorrect
3 ) Both are correct
4 ) 1 is correct but 2 is incorrect

In unit area, which stored polysaccharide provides maximum energy?

1) Starch
2) Lipids
3) Glycogen
4) Cellulose

Metal halide which is insoluble in water

 1. AgF
 2. AgI
 3. CaCl₂
 4. kBr

The type of chromosomes based on the number and location of the centromere found in human cell is:

(1) Acentric
(2) Submetacentric
(3) Polycentric
(4) Acrocentric

 The algae which help in the fixation of nitrogen belong to class

 1. Rhodophyceae
 2. Chlorophyceae
 3. Cyanophyceae
 4. Phaeophyceae