Throat, Anus , digestive system teeth
The factor that poses the greatest threat is loss of habitat. Have a nice day!
Answer;
-Zygote
When sperm and ovum unite at conception, a zygote results.
Explanation;
-Conception occurs when a sperm cell from a fertile man swims up through the vagina and into the uterus of a woman and joins with the woman's egg cell (ovum) as it travels down one of the Fallopian tubes from the ovary to the uterus.
-A zygote is the union of the sperm cell and the ovum. Also known as a fertilized ovum, the zygote begins as a single cell but divides rapidly in the days following fertilization. After this two-week period of cell division, the zygote eventually becomes an embryo.
The instructions on a chromosome are called-DNA
-Steel jelly