I left out the following sentences.

Question

Thank you.

1)Of (among?) the toothed whales Narwhal whales are his favourite. They are known for their unicorn-like tusk that grows (springs?) from their forehead, in the male of the species. This can be up to three meters long.
2)In conclusion, he says that though the populations of many marine species are decreasing very quickly, people have not been aware of (have ignored?) the problems with ocean wildlife because it is not visible.
3) It was nice (not: good) of Susanne, to forward my email to you.

Answer 1

1. use "Of" and put a comma in there where it's needed; use "grows" not "springs."

2. use "not been aware of" -- and then clarify what "it" refers to!!

3. Either adjective works; and delete that comma.