Why we have to attach all of the sources

Gravity when a person drinks large amount of water
May 3, 2020
Solution-Determine the chromosome constitution and
May 3, 2020

Why we have to attach all of the sources

We have to attach all of the sources. I am having trouble finding anything but examples and biology teacher notes. I have worked on this for 2 days and only have an opening statement that seems to pretty much sum up everything. I need to avoid unnecessary information but I feel I have limited resources. Can someone please elaborate of the test cross and its usefulness.