AP EAMCET Medical 24 Sep 2020 Shift 2 Paper

Iii understanding different types of symmetry, the term used as principal axis means:
1) A flat area that run throught any axis
2) An imaginary straight line joining two opposite points at the ends
3) An imaginary straight line joining the mid-point at one end and the mid-point at the opposite end
4) An animal having its body parts arranged in such a manner to exhibit symmetry