CBSE Questions for Class 12 Medical Biology Organisms And Population Quiz 2 - MCQExams.com

Omnivory refers to act of feeding on plants and animals; plants and animals are negatively affected. Mutualism is an association of organisms wherein both are benefitted. Parasitism is the relationship where one organism is benefitted at the expense of other. Predation refers to the act of feeding on other animals; predator is benefitted at expense of prey. Commensalism refers to the relationship wherein one organism is benefitted while other remains unaffected. Thus, the correct answer is A.

• Symbiosis is any type of close and long term biological interaction between two different biological organisms which may be mutualistic, commensalistic, or parasitic. Symbiosis is living together of unlike organisms. It is also known as physical attachment, in which the organisms have bodily union known as conjunctive symbiosis.
  
• Hence interacting populations are symbiotic i.e they can be mutualistic, parasitic or commensalistic..
• So, the correct answer is 'Symbiotic',

• Facultative means false and obligate means true. So, those parasites which cannot survive without their host are called obligate parasites, whereas, those parasites which can survive without a host are called facultative parasites.
• Green plants in genera such as Rhinanthus and Colpoon can grow independently of any host, but they also act opportunistically as facultative root parasites of neighboring green plants.

• Mutualism is a mutually beneficial relationship between individuals of two different species. Neither of the two is capable of living separately e.g., Nitrogen-fixing Rhizobium bacteria living in root nodules of leguminous plants.
• Protocooperation is a non-obligatory mutually beneficial relationship. E.g. Hermit crab and sea anemone.
  
• In commensalism is an interaction in which one organism is benefited and the other is neither benefited nor harmed, e.g., Barnacles are often attached to the surface of whales for shelter and obtaining more food.
  
• In ammensalism without deriving much benefit, one organism inhibits the other by secreting allochemics. The phenomenon is called antibiosis e.g., Trichoderma checks the growth of Aspergillus.
  
• Therefore, the correct answer is option D.

• The terms are given here describe the interaction between organisms in nature. When both the species benefit, the interaction is called mutualism.
• One species is harmed whereas the other is unaffected is called amensalism.
• Protocooperation is a positive interaction beneficial for both the interacting organisms but is not an obligatory interaction and both species can lead their independent lives without an intimate interaction.
• The interaction where one species is benefited and the other is neither benefited nor harmed is called commensalism. The relationship between the sea anemone and hermit crab is commensalism in which the hermit crab is protected from its predators.
• Therefore, the correct answer is option D.

Correct Option: B

Explanation:

In commensalism, one species is benefitted without the other being harmed. It is of two types periodic contact and continuous contact.
Some examples of periodic contact commensalism are jackal and hyenas accompanying big cats like tiger or lions for eating small bits of left over of prey's body.
Suckerfish attaches to the underside of shark and feed on small left over when the shark is feeding. Therefore, the correct answer is option B.

• Crab and sea anemone show mutualism in which hermit crab gets protection and sea anemone move from place to place.
• Sucker fish (Echeneis) and shark show commensalism. Sucker fish has a sucker or holdfast, which is a modified dorsal fin. It attaches to the underside of the shark and therefore remains protected. The fish obtains its food from small pieces of leftover when the shark is feeding on its prey.
• Cuscuta is an angiosperm, which is a total stem parasite on Cissus and other plants.
• Tiger is a natural predator of deer and kills deer to feed on it.
• So, the correct answer is option B.

• Mutualism is a mutually beneficial relationship between individuals of two different species. None of the two is capable of living separately. For example, nitrogen-fixing Rhizobium bacteria living in root nodules of leguminous plants.
• Commensalism is an interaction in which one organism is benefited and the other is neither benefited nor harmed. For example, Barnacles are often attached to the surface of whales for shelter and obtaining more food.
• In amensalism without deriving many benefits, one organism inhibits the other by secreting allochemicals. The phenomenon is called antibiosis. For example, Trichoderma checks the growth of Aspergillus.

• In predation, one organism called a predator captures, kills, and eats another organism, called prey. 
• Predators are generally carnivorous animals but some are herbivorous. Herbivores that destroy whole plants/seeds are also called predators e.g., birds like sparrows feeding on seeds.
• So, the correct answer is option C.

• In commensalism, one species is benefitted without the other being harmed. It is of two types - periodic contact and continuous contact. 
• Some examples of periodic contact commensalism are jackal and hyenas accompanying big cats like tiger or lions, for eating small bits of leftover of prey's body; sucker fish attaches to the underside of shark and feed on small leftover when the shark is feeding. 

Rafflesia is the largest and most magnificent flower in the world. It is total root parasite found in sea shores of Java and Sumatra and Sri Lanka. Vegetative parts of Rafflesia are highly reduced, represented by cellular filaments. These filaments which are the main part of the body resides inside the plant host. Hence, the correct answer is option D.