#13 Biology Class XII- Organisms and Populations (NEET, MHTCET) MCQ

 

1) Reduction in vascular tissue, mechanical tissue and cuticle are characteristics of 

(a) mesophytes  

(b) epiphytes  

(c) hydrophytes   

(d) xerophytes

Answer 

(d) xerophytes

 

 

2) Which of the following is a characteristic of biological community?

(a) Startification  

(b) Natality  

(c) Morality  

(d) Sex-ratio

Answer 

(a) Startification 

 

 

3) What type of human population is represented by the following age pyramid?

(a) Vanishing population    

(b) Stable population 

(c) Declining population    

(d) Expanding population

Answer 

(b) Stable population

 

 

4) The logistics population growth is expressed by the equation

(a) $\frac{\mathrm{dt}}{\mathrm{dN}}=\mathrm{Nr}\left(\frac{\mathrm{K}-\mathrm{N}}{\mathrm{K}}\right)$

(b) $\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left(\frac{\mathrm{K}-\mathrm{N}}{\mathrm{K}}\right)$

(c) $\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}$
(d) $\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left(\frac{\mathrm{N}-\mathrm{K}}{\mathrm{N}}\right)$

$\left(\frac{\mathrm{<span\; style="font-size:\; large;"><br></span>}}{}\right)$

$\left(\frac{\mathrm{<br>}}{}\right)$ Answer
(b) $\frac{\mathrm{dN}}{\mathrm{dt}}=\mathrm{rN}\left(\frac{\mathrm{K}-\mathrm{N}}{\mathrm{K}}\right)$

5) Cuscuta is an example of

(a) ectoparasitism  

(b) brood parasitims  

(c) predation  

(d) endoparasitims

Answer 

(a) ectoparasitism 

 

 

6) A sedentary sea anemone gets attached to the shell lining of hermit crab. The association is

(a) commensalism  

(b) amensalism  

(c) ectoparasitism  

(d) symbiosis

Answer 

(d) symbiosis

 

 

7) Which of the following is the most accurate comment on Earth’s carrying capacity (K)?

(a) K is smaller now than it was a thousand years ago. 

(b) The human population is still a long way from K. 

(c) Our technology has allowed us to keep increasing K. 

(d) When it comes to humans, the concept of K is irrelevant.

Answer 

(c) Our technology has allowed us to keep increasing K.

 

 

8) Which of the following would be true of a species with an opportunistic life history?

(a) Members of the species take a relatively long time to reach reproductive age. 

(b) They are regulated mostly by density-dependent factors. 

(c) They produce large numbers of offspring. 

(d) The population usually stabilizes near carrying capacity.

Answer 

(c) They produce large numbers of offspring.

 

 

9) A particular species of tropical fish has only a few offspring and takes care of them for an extended period. We might also expect the fish population to

(a) be controlled mostly by density independent factors. 

(b) show exponential growth. 

(c) live in a harsh environment. 

(d) be relatively stable near carrying capacity.

Answer 

(d) be relatively stable near carrying capacity.

 

 

10) Ecological niche is [NCERT Exemplar]

(a) the surface area of the ocean 

(b) an ecologically adapted zone 

(c) the physical position and functional role of a species within the community 

(d) formed of all plants and animals living at the bottom of a lake

Answer 

(c) the physical position and functional role of a species within the community

 

 

11) When birth rate equals death rate,

(a) a population grows rapidly. 

(b) the size of a population remains constant. 

(c) density-dependent limiting factors do not affect the population. 

(d) a population is in danger of extinction.

Answer 

(b) the size of a population remains constant.

 

 

12) According to Allen’s Rule, the mammals from colder climates have [NCERT Exemplar]

(a) shorter ears and longer limbs 

(b) longer ears and shorter limbs 

(c) longer ears and longer limbs 

(d) shorter ears and shorter limbs

Answer 

(d) shorter ears and shorter limbs

 

 

13) Salt concentration (Salinity) of the sea measured in parts per thousand is [NCERT Exemplar]

(a) 10 – 15 

(b) 30 – 70 

(c) 0 – 5 

(d) 30 – 35

Answer 

(d) 30 – 35

 

 

14) Formation of tropical forests needs mean annual temperature and mean annual precipitation as [NCERT Exemplar]

(a) 18–25°C and 150–400 cm 

(b) 5–15°C and 50–100 cm 

(c) 30–50°C and 100–150 cm 

(d) 5–15°C and 100–200 cm

Answer 

(a) 18–25°C and 150–400 cm

 

 

15) Which of the following forest plants controls the light conditions at the ground? 

[NCERT Exemplar]

(a) Lianas and climbers 

(b) Shrubs  

(c) Tall trees 

(d) Herbs

Answer 

(c) Tall trees

 

 

16) What will happen to a well growing herbaceous plant in the forest if it is transplanted outside the forest in a park? [NCERT Exemplar]

(a) It will grow normally  

(b) It will grow well because it is planted in the same locality  

(c) It may not survive because of change in its micro climate 

(d) It grows very well because the plant gets more sunlight

Answer 

(c) It may not survive because of change in its micro climate

 

 

17) If a population of 50 Paramecium present in a pool increases to 150 after an hour, what would be the growth rate of population? [NCERT Exemplar]

(a) 50 per hour 

(b) 200 per hour  

(c) 5 per hour 

(d) 100 per hour

Answer 

(d) 100 per hour

 

 

18) What would be the per cent growth or birth rate per individual per hour for the same population mentioned in the previous question (Question 11)? [NCERT Exemplar]

(a) 100 

(b) 200  

(c) 50 

(d) 150

Answer 

(b) 200 

 

 

19) A population has more young individuals compared to the older individuals. What would be the status of the population after some years? [NCERT Exemplar]

(a) It will decline 

(b) It will stabilise  

(c) It will increase 

(d) It will first decline and then stabilise

Answer 

(c) It will increase

 

 

20) At which point in the graph shown below would there be zero population growth (DN/Dt = 0) ?

(a) a 

(b) b 

(c) c 

(d) d

Answer 

(d) d

 

 

21) For a population that is stable in size, the following age distribution indicates that

(a) The population’s birth and death rates are both high. 

(b) The population’s birth and death rates are both low. 

(c) The population’s birth rate is low but its death rate is high. 

(d) The population’s birth rate is high but its death rate is low.

Answer 

(a) The population’s birth and death rates are both high.

 

 

22) Amensalism is an association between two species where [NCERT Exemplar]

(a) one species is harmed and other is benefitted  

(b) one species is harmed and other is unaffected  

(c) one species is benefitted and other is unaffected  

(d) both the species are harmed.

Answer 

(b) one species is harmed and other is unaffected 

 

 

23) Lichens are association of [NCERT Exemplar]

(a) bacteria and fungus 

(b) alga and bacterium  

(c) fungus and alga  

(d) fungus and virus

Answer 

(c) fungus and alga 

 

 

24) Which of the following is a partial root parasite? [NCERT Exemplar]

(a) Sandalwood 

(b) Mistletoe 

(c) Orobanche 

(d) Ganoderma

Answer 

(a) Sandalwood

 

 

25 ) According to population scientists, one of the factors responsible for limiting population is the 

(a) availability of food. 

(b) daily variation of environmental temperature. 

(c) time required for ecological succession. 

(d) life span of members of the population.

Answer 

(a) availability of food.