The sperm penetrates the ovum mainly
Mechanically
Chemically
Electrostatically
Thermally
Which of the following provides nutrition to sperm?
Both corpus luteum and macula lutea are
$A$ : The male urethra is longer than the female urethra.
$R$ : It carries both urine as well as semen.
Amphimixis means
Nervous system in vertebrates develops from