It seems to me you have done a very good job on these translations. Minor spelling points:contryside countryside mashrooms mushrooms.

Just some minor things about articles:

"Moreover, if a number of known plants, living on the land..." => Moreover, if the number of known plants living on the land...


"...then the number of living on the land animals is 12%..." => then the number of land animals is 12%...

"The weight of a raindrop is much more than a weight of an equal sized mosquito." =>...more than the weight of...

"This fact, and fine hairs all over his body leads..." => ...and the fine hairs...

Translation is difficult because of matters of personal taste in composition. This shows up in different ways to word things. People have different preferences about how to word things.

For example:
“The creators of the "Star Track" series at the time faced with a need of showing danger and death to the characters to provide interest of customers. But since killing the main characters was pretty expensive, they decided to sacrifice other ones, who have been replaced constantly. …”

There are minor points that appear to be incorrect here. But it does not sound 'natural'.

=>

The creators of the "Star Treck" series faced at the time a need to provide interest to viewers by showing danger and death to the characters. Killing the main characters was too expensive, so they decided to sacrifice other ones, who have been replaced constantly.