CBSE Questions for Class 11 Medical Biology Biological Classification Quiz 5 - MCQExams.com

Certaria is a kind of lichen which lives in close association with green algae. It is a very good source of laxative which makes bowel movement easy and loosen the stools. Most of these species are found at high latitudes, occurring on sand and shrub lands.

A lichen is a composite organism that arises from algae or cyanobacteria (or both) living among filaments of a fungus in a symbiotic relationship. The combined life form has properties that are very different from the properties of its component organisms. The fungus benefits from the symbiotic relation because algae or cyanobacteria produce food by photosynthesis. The algae or cyanobacteria benefit by being protected from the environment by the filaments of the fungus, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it. Thus, the correct answer is option C.

The contractile vacuole is actually a regulatory organelle which is present in protozoans and helps in regulating water balance by osmoregulation. It was earlier known as the pulsating vacuole. It helps in excreting excess water from the protozoans body outside in the surrounding environment.

The correct answer is C.

Solution

Correct answer is option D.

Explanation for correct option:

• Asexual reproduction: - It does not include the union of gametes or variation in the number of chromosomes.
• The generation that results from asexual reproduction inherits the genes of that parent.
• Asexual reproduction is the original form of reproduction for unicellular organisms such as archaea and bacteria.
• There are various asexual reproduction methods by which the unicellular organisms divide like fission, budding, vegetative propagation etc.

• Viruses possess nucleic acid (either DNA or RNA) enclosed in a protein coat called a capsid. 
• It does not possess any cellular structure. 
• They are inactive outside any living body. They can replicate only inside the living cells of other organisms.
• Viruses can be crystallized. The first virus to be crystallized is the Tobacco Mosaic virus.

• The mode of nutrition seen in fungi is saprotrophic or parasitic. 
• Saprotrophs gets nutrition from dead and decaying organic matter. 
• Parasites derive nutrition from living host.

Solution

Correct answer is option A.

Explanation for correct option:

• Mushrooms are edible fungus that can provide several important nutrients.
• Fungi are eukaryotic organisms which are heterotrophs.
• Fungi get their nutrition by absorbing organic compounds from the environment.
• Fungi obtain nutrients from dead, organic matter, hence they are called saprophytes.