3. a) Some nouns from the article are missing from the definitions below. How many can you find without looking back at the article?
2)
1) population (n.) [U] - all the people who live in one area, city or
country.
(n.) [U] - a process of making water, air, soil, etc.
dirty.
3)
(n.) [U; C] - when sb or sth becomes impossible
to see or find.
4)
(n) [C] - a person who carefully studies the topic
to find new facts or information.
5)
(n.) [U] – the process of something being made
worse.
6)
7)
8)
(n.) [U] - the state of being safe and protected
from danger.
(n.) [C; U] - a rise in the number.
(n.) [U] - physical harm to something that makes
it less attractive or useful.​