When blood is in the lungs,
where oxygen is plentiful, oxygen easily binds to the first subunit and then quickly fills up the remaining ones. Then, as blood circulates through the body, the oxygen level drops while that of carbon dioxide increases. In this environment, hemoglobin releases its bound oxygen.
False, I'd say. Mammals usually adapt based on environment. Now, I know predators are "apart" of the environment, but I don't think that'd be it. I'd bet more money on saying mammals evolve based on environment adaptation. Sorry if I didn't answer your question or if I didn't get my point across well.
The fertilized egg begins a rapid descent to the uterus. The period of rest in the tube appears to be necessary for full development of the fertilized egg and for the uterus to prepare to receive theegg. ... At the end of this transition period, the embryo becomes a mass of very organized cells, called a blastocyst.
