Answer:
Between one-third and one-half of all fertilized eggs never fully implant. A pregnancy is considered to be established only after implantation is complete
<span>Species is a group of reproducing populations that are isolated from other groups. </span>
<span>-The nervous system processes information from receptors that detect changes in the environment.
-The nervous system coordinates the systems of the body.
-The nervous system sends out appropriate responses to react to changes in the environment.
-The nervous system maintains homeostasis.</span>
