How many statements are correct about frogs?

(a) A male frog has copulatory pad on the first digit of the hindlimbs.

(b) Fertilisation is external and takes place in water.

(c) Frog is a ureotelic animal.

(d) Hepatic portal system is present but the renal portal system is absent.

(a) A male frog has a copulatory pad, but it's located on the inner surface of the first digit of the forelimbs, not the hind limbs. So, this statement is incorrect.

(b) In most frog species, fertilisation is external and occurs in water.

(c) Frogs are ureotelic animals, meaning they primarily excrete urea as a waste product of protein metabolism.

(d) Frogs have both hepatic and renal portal systems.