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Organisms and Populations

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

The population of an insect species shows an explosive increase in numbers during rainy season followed by its disappearance at the end of the season. What does this show?

• S-shaped or sigmoid growth of this insect

• The food plants mature and die at the end of the rainy season

• Its population growth curve is of J-type

• The population of its predators increases enormously

C.

Its population growth curve is of J-type

Its population growth curve is J-shaped in which density increases rapidly in exponential fashion and then stops abruptly as environmental resistance or another limiting factor becomes effective more or less suddenly.

Its population growth curve is J-shaped in which density increases rapidly in exponential fashion and then stops abruptly as environmental resistance or another limiting factor becomes effective more or less suddenly.

To live in groups is beneficial because :
• feeling of security
• can obtain food easily
• Partner is available for mating
• All the above

D.

All the above

Ants give information to their companions :
• by dancing
• by secretion of pheromones
• by making sound
• by defecating

B.

by secretion of pheromones

The number of births during a given period in the
population that are added to the initial density is

:
• Natality
• Mortality
• Migration
• Immigration

A.

Natality

The departure of a individual from a population is called :
• Natality
• Mortality
• Immigration
• Emigration

D.

Emigration

Population density is denoted by the symbol
• N
• D
• M
• D

A.

N

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