Question

Which of the following shows bilateral symmetry?
A. Human
B. Housefly
C. Both A and B
D. None of the above

Answer 1

Hint: Almost every vertebrate and a large number of invertebrates are bilaterally symmetrical. This means the body can be divided into two similar halves only in one plane. This is the symmetry in which the opposite sides are similar. That is the external appearance is the same on the left and right sides in a sagittal plane.

Complete answer: The body plans of most of the animals, including humans, exhibit mirror symmetry, also called bilateral symmetry. They are symmetric about a plane running from the head to the tail or toe. The human body shows bilateral symmetry. Bilateral symmetry is the symmetry in which similar anatomical parts are arranged on opposite sides of a median axis so that only one plane can divide the individual into essentially identical halves. There are actually some of the real advantages of having bilateral symmetry.
-The fact that we have two eyes and ears means that we can see and hear more than most of the animals with radial symmetry.
-Bilateral symmetry also causes the formation of the head and the tail area.
-Another advantage of having this symmetry is that the bilateral symmetry allows for the development of a more thorough nervous system that can control the body which is located in the head region.
Therefore the correct answer is option A.

Note: Over the years, scientists have come up with a number of hypotheses about what that reason might be for the bilateral symmetry. According to one of the scientists, a body that is bilaterally symmetrical is easier for the brain to recognize while in different orientations and positions, hence making visual perception easier.