CBSE Questions for Class 12 Medical Biology Organisms And Population Quiz 5 - MCQExams.com

• A predator is an organism that hunts, catches, kills, and eats other animals.
• Parasitism is a type of symbiosis where one organism (the parasite) benefits and the other (the host) is harmed. 
• A host is an organism that harbors a parasite, or a mutual or commensal symbiont, providing nourishment and shelter. 
• Amensalism is an association between organisms of two different species in which one is inhibited or destroyed and the other is unaffected.
• So, the correct answer is option D.

• Predation is a type of interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked). 
• Parasitism is a relationship between species, where one species, the parasite, benefits at the expense of the other, the host. 
• Symbiosis is the relationship between two or more organisms living closely together and cannot survive without each other. 
• Exploitative competition occurs when consumption of a limiting resource by one species that makes the resources unavailable for consumption by another. 

A.Correct option: D

B.Explanation for the correct option.

• Epiphytes are air plants that grow on other plants. They are not anchored in the soil and use rainwater and air as a source of nutrition. They are found in moist tropical areas. Prairie is a grassland of North America where trees and tall shrubs are rare to find and so for this reason epiphytes are not found in the prairie.

   Explanation for incorrect pairs:

   Option (A): Acacia trees are very common in the savanna. The fire-resistant feature of their long taproots helps them survive the drought conditions in the savanna. 
  Option (B): Coniferous forests consist mostly of conifers that tend to be evergreen. Evergreen plants have foliage that remains green and functional for more than one growing season. 

  Option (C): Tundra is a treeless polar desert with long and dry winters. Permafrost is any ground that remains frozen. It is a common feature of the tundra

• $${Nepenthes}$$ is both a primary producer and consumer.
• It can photosynthesize which makes it a primary producer. 
• It grows in nitrogen-deficient soils and hence feeds on insects for nitrogen, which makes it a carnivore.

• Natality or birth rate is the rate of production of new individuals per unit of population per unit of time through birth, hatching, germination, and vegetative propagation. 
• If the natality rate increases the mortality rate the population rapidly increases.
• Natality (birth rate) is calculated as the number of births per thousand individuals per year.

A population is a unit of biotic community made up of near permanent group of an interbreeding individual of a species found in a space or geographical area at a particular time. It is called local population or deme. Increasing population is a challenging issue for the developing country like India. If the population increases more than its carrying capacity it may lead to food crisis resulting in famines, hunger and poor health, acute shortage of shelter and clothing. Spreading awareness among the people about the ill-effects of increasing population may be helpful to control the over increasing population. So, the correct answer is option D.

• Mortality is the relative frequency of deaths in a specific population. 
• Infant mortality rate refers to the number of children that die before the age of five years as a proportion to $$1000$$ live births in that particular year.

Natality (birth rate) is the rate of production of new individuals per unit of population or unit time. The population increases when the natality rate is more than the mortality rate. The calculation for determining crude birth rate is (number of births) x 1000 / estimated population at mid-year. So, the correct answer is option D.