Good studies overall;
However I feel like the still life with the onions and the pear: Those three items specifically could use more contrast. I can see them, but I feel like you should push it a little more. Perhaps make the values on the onions and the pear more dynamic? Add some darks? I think the problem is with those three things - try adding some darks and see where it takes you. Don't worry about the fabric behind the food though, that seems like it's got enough going on for now.
Doctors heal you, Artists immortalize you.
"Those who can, do. Those who can't, teach" - bullshit.
The usual staples for anatomy: