Since Jiskha doesn't have a biology expert at this time, please try posting your questions at this site.
http://www.biology-online.org/biology-forum/
In addition, be sure to make really good use of KhanAcademy!
https://www.khanacademy.org/science/biology
Choose from the general topics at the right and then find the specifics you need within each topic.
If there are two sets of 21 chromosomes in a rats lung cell, how many total chromosomes are there in a cell that undergoes mitosis?
Answer: 42
2 answers
http://www.khanacademy.org/science/biology
1 answer