Question

The opening of the rectum to the exterior of the body
A. Anus
B. Uvula
C. Vulva
D. Vagina

Answer 1

Hint: The opening of the end of the alimentary canal by which solid waste matter is released out the body is the answer to this question.
It is present on the dorsal side of the human body.

Complete answer:
The digestive system has two openings – the mouth and the anus.
1. The mouth is present in the starting of the alimentary canal and present in the ventral surface of the human body and helps in the intake of food.
2. The anus is the terminal opening of the rectum that is present in the dorsal surface.
It helps to release the waste materials.
3. The main function of the anus is to control the exit of feces from the body during an act of defecation.
4. There are two sphincters present in the anus.
These are the internal anal sphincter and the external anal sphincter.
5. The inner sphincter is involuntary in nature and the outer is voluntary.
6. The anus is located behind the perineum – a location behind the vagina of females and behind the scrotum of males.

Additional information: The word anus comes from the Latin word anus which means ring or circle. It is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the removal of feces, which is a residual semi-solid waste that forms from the undigested food such as bones, cellulose or lignin, dead or excess gut bacteria and other endosymbionts, etc.

So, the correct answer is Option A. Anus.

Note: All animals release waste materials, for example, amphibians, reptiles, and birds use the cloaca for their excretion of liquid and solid wastes and also for copulation and egg-laying.