Besides air pollution, four other important types of pollution are soil, water, waste, and
a.
dust
b.
wind
c.
cloud
d.
noise

from the conditions of the working class in england by friedrich engels,the main idea is :

the triple alliance. germany and austria-hungary were already allies by 1879 when, worried about a threat from russia, they formed the dual alliance. italy joined the group in 1882. there was a concern about a possible attack from france and the alliance needed powerful friends to defend it.