'Man's' in the Bible

I saw that all labor and all skillful work is due to a man’s jealousy of his friend. This too is futile and a pursuit of the wind.

All man’s labor is for his stomach,yet the appetite is never satisfied.

Who is like the wise person, and who knows the interpretation of a matter? A man’s wisdom brightens his face, and the sternness of his face is changed.

For every activity there is a right time and procedure, even though man’s troubles are heavy on him.

A wise man’s heart goes to the right,but a fool’s heart to the left.