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Organisms and Populations · Question 31

NEET (UG) 2020MCQEasy📈 Topic in 100% papers+4−1
1

Secondary metabolites such as nicotine, strychnine and caffeine are produced by plants for their

  1. Nutritive value
  2. Growth response
  3. Effect on reproduction
  4. Defence action

Answer

(4) Defence action

Solution

As per NCERT, plants have evolved chemical defences against herbivores (grazers and browsers): they produce and store chemicals such as nicotine, caffeine, quinine, strychnine and opium.

These chemicals make the herbivores sick, inhibit feeding or digestion, disrupt reproduction or even kill them.

∴ They are produced for defence action.

Answer: (4)

NEET (UG) 2020

Keep practising — Organisms and Populations

2

Which of the following is not an attribute of a population?

  1. Natality
  2. Sex ratio
  3. Mortality
  4. Species interaction
NEET (UG) 2020
3

Niche is

  1. all the biological factors in the organism’s environment
  2. the physical space where an organism lives
  3. the range of temperature that the organism needs to live
  4. the functional role played by the organism where it lives
NEET 2018
4

Which one of the following population interactions is widely used in medical science for the production of antibiotics?

  1. Commensalism
  2. Mutualism
  3. Parasitism
  4. Amensalism
NEET 2018
5

Natality refers to

  1. death rate
  2. birth rate
  3. number of individuals leaving the habitat
  4. number of individuals entering a habitat
NEET 2018
6

In a growing population of a country,

  1. pre-reproductive individuals are more than the reproductive individuals
  2. reproductive individuals are less than the post-reproductive individuals
  3. reproductive and pre-reproductive individuals are equal in number
  4. pre-reproductive individuals are less than the reproductive individuals.
NEET 2018
7

Asymptote in a logistic growth curve is obtained when :

  1. K > N
  2. The value of 'r' approaches zero
  3. K < N
  4. K = N
NEET 2017
8

Plants which produce characteristic pneumatophores and show vivipary belong to :

  1. Halophytes
  2. Psammophytes
  3. Hydrophytes
  4. Mesophytes
NEET 2017
9

Mycorrhizae are the example of :

  1. Fungistasis
  2. Antibiosis
  3. Mutualism
  4. Amensalism
NEET 2017
10

It is much easier for a small animal to run uphill than for a large animal, because -

  1. The efficiency of muscles in large animals is less than in the small animals
  2. Smaller animals have a higher metabolic rate
  3. It is easier to carry a small body weight
  4. Small animals have a lower O2 requirement
NEET 2016 (Phase 1)
11

When does the growth rate of a population following the logistic model equal zero? The logistic model is given as dN/dt = rN(1-N/K)

  1. When death rate is greater than birth rate.
  2. When N/K equals zero.
  3. When N/K is exactly one.
  4. When N nears the carrying capacity of the habitat.
NEET 2016 (Phase 1)

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