Give an example of the following

1.  Roundworm

2.  Fish possessing poison sting

3.  A limbless reptile/amphibian

4.  An oviparous mammal

(a) Roundworm — Ascaris
(b) Fish possessing poison sting - Trygon
(c) A limbless reptile/amphibian — Ichthyophis
(d) An oviparous mammal — Duck billed platypus.