Are there any Biology teachers that could check my answers for me?

Answer 1

I'm sorry, but Jiskha doesn't have any regular biology tutors.

Try this site.

http://www.biology-online.org/biology-forum/

Answer 2

In addition, be sure to make really good use of KhanAcademy!
http://www.khanacademy.org/science/biology
Choose from the general topics at the right and then find the specifics you need within each topic.

Answer 3

A police car approaches a large wall at 51m/s. Its siren emits a 980 Hz signal.

What is the frequency of the reflected sound observed by the officer