Since I do not have the passage i am unable to answer
Warm the air because, when water evaporates the cool water, it makes the air warmer, the warmer the air is, water will evaporate more
Yes because it has been an importance to all cultures through time in my opinion. It helps people mentally this includes the community and romantic partners be more loving and kind. Romance can be seen as more of a desire than a necessity for some people though so it really depends on your opinion.
AB= 2x+20 cm
BC= 8 cm
AC= x+20 cm
AC= AB + BC
x + 20 = 2x + 20 + 8
2x - x = 20 - 20 - 8
x = -8
AB= 4 cm
BC= 8 cm
AC= 12 cm