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A student examined a particular plant cell through its various stages of growth. After making various measurements, he realised that the increase in cell size was largely due to enlargement of the central vacuole rather than an increase in the amount of cytoplasm. Why might this be an advantageous strategy for the cell?

AEnlarging the cytoplasm would make the cell less turgid.
BEnlarging the vacuole would make it unnecessary for the cell wall to stretch.
CEnlarging the vacuole would minimise any lowering of the surface area - volume ratio of the cytoplasm.
DAll of these

Select the option that correctly fills the blanks in any two of the given statements.
(i) ______ refers to the plants found in a particular area.
(ii) ______ species are those which are going to be extinct in near term future.
(iii) The lion tailed macaque is included in ______ species in red data book.
(iv) A place rich in ______ species is called hotspot.

A(i) Fauna, (ii) Endangered
B(iii) Endangered, (iv) Endemic
C(i) Flora, (iii) Vulnerable
D(ii) Rare, (iv) Endangered

Which graph shows changes that occur in a river after being polluted by sewage?

A

B

C

D

Identify I, II and III in the given flow chart and select the correct option.


A

B

C

D

The diagram shows a bubble at the bottom of a pool. Assuming that the temperature of the pool is constant throughout the water, which of the following describes the change of the pressure and the density of air in the bubble as it rises to the surface?


--------Pressure------Density
AIncrease--------Increase
BIncrease--------Decrease
CDecrease-------Increase
DDecrease-------Decrease

Five blocks, B₁, B₂, B₃, B₄ and B₅ of different masses are connected by four identical strings S₁, S₂, S₃ and S₄ as shown in the figure. They are pulled by a steadily increasing force F. Which of the following strings is most likely to break?


AS₁
BS₂
CS₃
DS₄

Three threads P, Q and R of equal weights were taken and immersed in water for one minute. They were then taken out and weighed again. The observations are shown in the given table.

Clothes made from which thread will be most effective when worn in winter and why?

(A) P, because it is bad conductor of heat

(B) Q, because it has lot of air spaces in between its fibres

(C) R, because it has no air spaces in between its fibres

Read the statements given by three students.

Which out of the following children made wrong statements?

A Naina and Mahi
B Mahi only
C Kartik only
D Mahi and Kartik.

Study the given flow chart carefully and answer the question.
Which group lists the items that can replace R in the flow chart?



                 P                          Q                        R
AIce cube              Oxygen             Cold Drink
BOxygen                Hydrogen           Water Vapour
CCoca cola               Milk                  Vinegar
DWater Vapour       Oxygen                 Milk

Following are the characteristics of a type of soil.

1. It has poorvery large water-holding capacity
2. It tends to be very dense
3. has the smallest particle size of any soil type

Which of the following type of crops is suitable to grow in the soil mentioned above?

AWheat
BGroundnut
C Coconut
DPaddy