Which of the following statements is incorrect. Human spermatozoa normally
At a concentration of $1$ million/ml of ejaculate will fertilize the ovum
Are released in large numbers after a few days abstinence
Contain enzyme in their head which helps in penetration of ovum
Move with the help of their tails
Notochord, skeletal system and dermis of the skin are the derivatives of
The extra embryonic membranes of the mammalian embryo are derived from
The following graph of relative concentrations of the four hormones present in the blood plasma of a woman during her menstrual cycle. Identify the hormones $A, B, C$ and $D$
In both chordates and non-chordates intestine develops from