The soon to be male organism, developing from the zygote, receives or inherits the X chromosome from his mother. His father provides him the y chromosome, the smaller of the 2 sex chromosomes.
Answer:
Lizards / Reptiles
(Scientific four-legged snake is: Tetrapodophis)
Explanation:
couldn't add answer ^^ ignore comment :-)
I would say that the fishes exhibited the greatest diversity (though the brachiopods also had considerable diversity) and mostly were of the ostracoderms (with a platey or shell-like skin and no jawbone) which exhibited many varieties and also the placoderm which had gills, a jawbone and fins so was developing characteristics of modern fish.
The abdominal wall muscle that is most superficial of the oblique muscles is the rectus abdominis (or A)
