Botany MCQs for NEET — Practice Questions with Answers

(a) A single species might show high diversity at the genetic level over its distributional range. India has more than 50,000 genetically different strains of rice, and 1,000 varieties of mango.

(b) : Phosphorus is a major constituent of biological membranes, mucleic acids and cellular energy transfer systems. Many animals also need large quantities of this element to make shells, bones and teeth. The natural reservoir of phosphourus is rock, which contains phosphorus in the form of phosphate. When rocks are weathered, minute amounts of these phosphate dissolve in soil solution and are absorbed by the roots of the plants. Herbivores and other animals obtain this element from plants.

(b) Benthos is the community of organisms which live on, in, or near the sea bed, also known as the benthic zone. As no light is available in this zone of sea, the energy source for deep benthic ecosystem is often organic matter from higher water column which drifts down to the depths. This dead and decaying matter sustains the benthic organisms, and therefore, most organisms in benthic zone i.e., in deep oceanic waters, are scavengers or detritivores.

(d): Keystone species are species which have significant and disproportionately large influence on the community. Removal or decrease in their number causes disruption in structure and function of community. For example in intertidal regions starfish feeds on mussels. Removal of starfish leads to dominance of mussels that excludes algae and browsing species. In tropical rain forests, fig trees function as keystone species as they provide fruits to a number of animals during the period of food scarcity.

Energy flow is always unidirectional and it follow IInd law of thermodynamics. Energy is transferred from one tropic level to another trophic level but does not revert back.

In a stable ecosystem, availability of nutrients, limits the number of trophic levels.

Factual

Cellular respiration and photosynthesis are important parts of the carbon cycle. The carbon cycle is the pathways through which carbon is recycled in the biosphere. While cellular respiration releases carbon dioxide into the environment, photosynthesis pulls carbon dioxide out of the atmosphere.

Primary production is not increased with increasing latitude .

Most grassland plants are herbaceous. This means they are green and leafy and have little or no woody tissue. Also, they have shoots that emerge from beneath the ground.