
★ Skin Structure, Growth, & Nutrition Quiz
the pigment produced to protect the skin from the effects of ultraviolet run rays is
A. keratin
B. melanin
C. elastin
D. collagen
Topics:
Coronary Heart Diseases Shoulder Microorganism - Diseases Atoms and Radioactivity Oral Surgery Orthopaedic Neurology Population Genetics Environment Healthy Living Vocabulary Cardiovascular Diseases EM Spectrum Components of Blood ology & phobia Physical Activity EyesOther quiz: Reproduction
During spermatogenesis, which of the following cells is the first to become haploid?
A. primary spermatocyte
B. secondary spermatocyte
C. sperm cells
D. spermatid
E. spermatogonium