mankind

Ответ от Владимир Попов[гуру]
Разницу видно через толкование на английском.
mankind - более узкое в своем значении
humanity - содежит подтекст (человечность, гуманность)
man‧kind [uncountable]
all humans considered as a group [= humankind, man; ↪ womankind]:
Since earliest times, mankind has been fascinated by fire.
one of the most important events inthe history of mankind
hu‧man‧i‧ty
1 [uncountable]people in general:
We want a clean healthy environment forall humanity.
crimes against humanity
2 [uncountable]kindness, respect, and sympathy towards others [≠ inhumanity]:
a man of deep humanity
3 [uncountable]the state of being human rather than an animal or machine
common/shared humanity
We must never forget our common humanity.
4
(the) humanities
[plural]subjects of study such as literature, history, or art, rather than science or mathematics [= (the) arts]