Помогите плиз : НОК чисел 2 4 и 7

Плиз помогите срочно...

What dense..........! We can hardly see anything.

a) heat

b) frog

c) fog

d) drought

Пожалуйчта помогите!
 

Task 2. Complete each sentence with one of the words or phrases below (5 points).

human beings, environment, pollute, insects, prohibited

On the Earth live human beings, animals, birds, fishes, 1) … and plants. Now 2) … are killing our planet.  People 3) … natural homes of animals. Luckily many people care about the 4) … . They say polluting should be strictly 5) … .