Hello, is it possible to take two science classes in my Senior year? I have already signed up for AP Biology but I also want to take Environmental Science (Honors) at the same time. Plus this will be great for my major which is Biology/Environmental Studies.
Depends on your school, but usually yes unless there are scheduling conflicts.
Thankies 
It can be good to double up in science if it reflects what you want to pursue. Ask your GC.