Question

Which are density-dependent factors that limit population size?
I.Disease
II.Space
III.Earthquake
(a)I only
(b)II only
(c)III only
(d)I and II only
(e)II and III only

Answer 1

Population is the number of organisms that live in a particular geographic area of the same group or species and can interbreed. It is the number of people living in town or city, country or world.

Complete answer:
Disease and space are density-dependent factors that limit the population size. The number of individuals per unit area is defined as the population density. The disease is a density-dependent factor as the number of individuals in a given area is vulnerable to more chances of people getting affected by the disease. The area where any activity can be carried out is a space and more number of individuals in a given area will create less space. Hence it is also a density-dependent factor. This may cause reduced fertility which is known as the Allee effect. Locating sexual mates and increased inbreeding are the causes of low population densities by reduced fertility. A condition that affects the structure and functioning of a body of an organism is known as a disease that is not due to any external injury.

Additional Information: The movement of the plates of the earth's crust or the shaking of the surface of the earth is known as an earthquake which results in a sudden release of energy in Earth's lithosphere which creates certain waves known as seismic waves. It can vary its range from a weakness that cannot be felt to the violence which can propel objects and people into the air with huge destruction around the entire city. The distance from the epicenter will affect the range of the earthquake which can be severe at its center.

So, the correct answer is 'I and II only'.

Note: The population of the world increases by about 83 million per year and is continuing to increase. Earthquakes affect 3.5 million people every year which results in a loss in their life and damage to their homes. The population of Europe is shrinking whereas the African population is growing day by day.