Comprehension:
In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank.
The rise in the Irrawaddy dolphin (1) _______ in Chilika can be attributed to the eviction of (2)  _______ fish enclosures.After thousands of hectares of Chilika lake were made (3) _______ free, Irrawaddy dolphins found unobstructed area for movement. (4) _______, due to the COVID-19
lockdown last year, there were comparatively fewer tourist boats on Chilika lake, which made it (5) _______ for dolphins to move from one part of the lake to another.

Select the most appropriate option to fill in blank no. 1.

The correct option to fill in blank (1) is population.

Let's analyze the context of the passage:
The sentence reads: "The rise in the Irrawaddy dolphin (1) _______ in Chilika can be attributed to the eviction of..."
The sentence discusses the increase in the number of dolphins in Chilika lake. We need a noun that denotes the collective group or number of individuals of this species in a specific geographic area.

Let's evaluate each option:
1. population: In biology and ecology, a population is defined as a group of individuals of the same species inhabiting a given area. The term "dolphin population" is the standard and most precise term to describe the total number of dolphins in the lake. Therefore, "rise in the Irrawaddy dolphin population" fits perfectly.
2. clan: A clan refers to a close-knit group of families or social units. While some marine mammals live in pods or clans, the term is not used to describe the total count of a species across a large ecosystem like a lake.
3. natives: "Natives" refers to people or organisms associated with a place by birth. It is grammatically incorrect and awkward to say "dolphin natives" in this context.
4. inhabitants: "Inhabitants" refers to residents of a place. While dolphins are indeed inhabitants of Chilika, the phrase "rise in the Irrawaddy dolphin inhabitants" is not standard English usage when referring to ecological statistics and counts.

Hence, population is the most appropriate word to fill in the blank.