183. The term ‘flora’ in the context of natural vegetation refers to

A. assemblage of plant species living in association with each other in a given environmental frame
B. plants of a particular region or period, listed by species and considered as a group
C. a large tract covered by trees and shrubs and its administration for assessing economic benefits
D. role played by species of animals in the maintenance of ecological balance
✅ The correct answer is option B.
The term ‘flora’ in the context of natural vegetation refers to plants of a particular region or period, listed by species and considered as a group.

185. The major cause of species extinction is

A. agricultural activities
B. extraction (including mining, fishing, logging)
C. development (human settlements, industry)
D. habitat loss and degradation
✅ The correct answer is option D.
Species endangerment and extinction have three major anthropogenic causes—overhunting or overharvesting; introduction of nonnative species, including the spread of disease; and habitat degradation or loss. All three causes probably were factors in prehistoric as well as modern times.