Prior to ejaculation,__________ in the plasma membrane of the sperm prevents premature release of__________.

The gene that codes for the testis-determining factor (TDF) is found in or on the__________.

Complement C3b protein coats bacteria and stimulates phagocytosis by__________ during a process called__________.

Neonatal immunity depends on IgG and IgA acquired through the placenta and colostrum, respectively.

Changes called male climacteric are a consequence of a(n)__________.

Primary germ layers are formed during__________.

The process that makes it possible for sperm to penetrate the egg is called__________.

During implantation, the trophoblast divides into a deep layer called the__________, which is composed of individual cells.

The spheroidal stage of early prenatal development with about 16 to 64 cells is called a(n)__________.

What is the earliest sign of puberty in young females?