Question

Which trait was most important in the development and advancement of modern fish?

A) a lower jaw
B) eggs with shells
C) 4-chambered heart
D) live birth of young

Answer 1

A. a lower jaw. hope this helps

Answer 2

Answer: Option A - A lower jaw.

Step-by-step explanation:

• The earlier fishes used to be jawless (Agnathans).

• The most important trait used in the development of advanced fishes was the development of lower jaw.

• This lower jaw was primarily developed to facilitate the biting.

• Later on the complete jaw was developed which facilitated first in breathing and then was utilised for feeding.