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A scientist conducted a study on four different species of organisms (W, X, Y and Z) that are related in an aquatic food chain. He estimated the total number of individuals in the population of each species and the average biomass of each individual.


Which of the following shows the correct relation of these species in a food chain?

AZ → Y → W → X
BX → W → Z → Y
CX → W → Y → Z
DZ → W → X → Y

Equal sized square pieces of three different fabrics X, Y and Z were taken and spread out on a floor. Three small similar metal balls were each rolled with equal force from one end diagonally to the other end of fabric piece. Time taken by the balls to reach other end of fabric was noted to be as follows:


Now, select the correct option regarding this.

AFabric Z can be obtained from seeds of a plant and fabric Y can be obtained from stem of a plant.
B Fabric Z can be obtained from the stem of a plant and fabric Y can be obtained from larva of an animal.
CFabric Y can be obtained from the fur of an animal and fabric X can be obtained from larva of an animal.
DFabric Y can be obtained from the fur of an animal and fabric Z can be obtained from larva of an animal.

The speed of a train increases at a constant rate a from zero to v, and then remains constant for an interval, and finally decreases to zero at a constant rate b. If L be the total distance travelled, then the total time taken is

A
B
C
D

There is a certain relationship between fig. (i) and (ii). Establish a similar relationship between fig. (iii) and (iv) by selecting a suitable figure from the options which will replace (?) in fig.(iv).




A
B
C
D

A comet is different from a planet because _________ .

AIt has light of its own
BIts orbit is more elliptical
CIt does not orbit around a host star
DIt is oval in shape

Ali was asked about importance of non-living things. He made four statements. Select the correct one.

A They are needed by some living things to feed upon.
B Living things need a man-made, non-living thing to breathe.
C Non-living things are always required by living things to move from one place to another.
D Both (A) and (B)

The given diagram shows a respirometer that is used to measure gaseous exchange in pea seeds. The apparatus is maintained at a constant temperature.


Which of the following is incorrect regarding this?

AThe gas pressure in X will fall as O₂ is absorbed during respiration and CO₂ is absorbed by potassium hydroxide solution.
BThe fluid level at Y will fall to compensate the loss of pressure in X.
CThe gas pressure at X will rise as O₂ is given out by seeds and CO₂ is released by potassium hydroxide solution.
DThe fluid level at Z will rise due to loss of pressure at X.

Observe the given figures carefully.


The reversible changes. is/are:

A(1) only
B(1) and (2)
C(3) only
D(2) and (3)

Which of the following events will result in a decrease in the population of butterflies?
1. Increase in the population of birds
2. Increase in the supply of plant fertilisers
3. Reduction in the number of green plants
4. Increased use of insecticides by man on gardens and green belts

A1, 2 and 3
B1, 2 and 4
C1, 3 and 4
D2, 3 and 4

A scooterist moving with a speed of 36 km h^-1 sees a child standing in the middle of the road. He applies the brakes and brings the scooter to rest in 5 s just in time to save child. If mass of the scooter and driver is 300 kg, the average retarding force on the scooter is

A6 × 10⁷ g cm s^-2
B6 × 10⁴ g m s^-2
C6 × 10⁵ kg cm s^-2
D6 × 10³ kg m s^-2