CBSE Questions for Class 12 Medical Biology Organisms And Population Quiz 4 - MCQExams.com

• The parasite is defined as the organism which survives on the body of the host organism for food and space to survive. 
• The Anopheles mosquito feeding on the blood of animals, the human fetus developing in the womb of the mother, and derives the nourishment from the mother and the cuckoo laying eggs in the crow's nest are the interactions of the living organisms. 
• The head lice living on the human scalp and lays eggs on hair cannot survive without this habitat and completely depends on the host. 

Solution

Correct answer is option C.

Explanation for correct option

• Insectivorous plants are the plants that trap insects and withdraw nutrition from them. Example: Drosera, Nepenthes, Utricularia etc
• Bladder traps are found in bladderwort plants (genus Utricularia) which actively suck in small organisms using a partial vacuum in order to obtain nutrition. 
  

• Plants convert light energy from the sun into chemical energy (food) by the process of photosynthesis. 
• Animals eat plants and use that same chemical energy for all their activities. 
• Thus, the correct answer is option C.

• Mutualism is the relationship in which each individual benefits from the activity of the other (Beneficial to both A and B).
• Competition is a contest between organisms, animals, individuals, groups, etc., for territory, a niche, or a location of resources, for resources and goods, mates, for prestige, recognition, awards, or group or social status, for leadership (Harmful to both A and B).
• Parasitism is a relationship between species, where one species, the parasite, benefits at the expense of the other, the host (Beneficial to A and harmful to B). 
• Predation is a biological interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked). Predators may or may not kill their prey prior to feeding on them, but the act of predation often results in the death of its prey and the eventual absorption of the prey's tissue through consumption (Beneficial to A and inhibitory for B).
• Commensalism is a relationship between two organisms where one organism benefits from the other without affecting it (Beneficial to A and no effect for B). 

A parasite is an organism that depends on another organism, known as a host, for food and shelter. A parasite usually gains all the benefits from this relationship and kill the host cell. But the some of the parasites which benefit from the host do not kill the host. Example stem parasites in plants.Therefore, the correct answer is option B.

Solution

Correct answer is option C.

Explanation for correct option:

• An atmosphere is a layer of gas or layers of gases that envelope a planet, and is held in place by the gravity of the planetary body.
• It protects living organisms from temperature extremes and excessive UV radiation.
• If there were no atmosphere around the earth, the temperature would get affected.
• Also there would be  no ozone layer that would be used as a protection layer against harmful radiations.
• The earth would become Like a moon that had temperatures ranging from −190∘C to 110∘C.

Solution:

• Correct answer is option C 

• Exponential phase or log phase is phase where maximum growth takes place in population. 
• Maximum growth is seen here because of availability of food and requirements are in plenty amount and there is no competition in exponential phase