What is the term used for populations leaving an area?

Of seawater increases with decrease in the temperature. therefore, the cold water sinks to the deeper layers at the bottom

One important development during the 3rd trimester that will insulate the infant against changes in temperature is a. the deposition of fat under the skin b. the closing of the septum between c. the atria of the heart d. the beginnings of lung functioning e. the beginnings of light and sound sensing

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.