The crayfish have its nerve cord on the ventral side rather than on the dorsal side. The ventral side is under the Crayfishes' exoskeleton, as opposed to the dorsal side where the exoskeleton is . If it is attacked it will be from the dorsal side and the nerve cord would be snapped easier. The function of the nerve cord is that if it gets attacked by a predator they will go for the top and it will still be able to move.
A zinc, Zn, atom contains 30 protons inside the nucleus and 30 electrons outside the nucleus. hope this helped :)
B - To live in less extreme environments than most Archaebacteria.<span>♥</span>
That question is confusing. Cells obviously take from its parent cells, which means that DNA is combined from both mom and dad in a unique way. That can cause the offspring to have either the mom's or dad's eyecolor. So the "different genes" part apply to that because for each feature of the offspring it is a complex combination of mom and dad. What I don't get is the different cells. there are these things called stem cells which are basically cells that can be anything in the body when there's a need for it. A stem cell can be a nerve cell or muscle cell for example. So i don't think it requires genes to be exact to form a cell. I hope you get what I'm trying to say
2 the Double Helix by James Watson and what mad pursuit by Francis crick
