Question

The human sperm consists of the head, middle piece, and tail. What purpose does the tail in the sperm serve?

Answer 1

Hint: 1) In anisogamous sexual reproduction, sperm is the male reproductive cell, or gamete (forms in which there is a larger, "female" reproductive cell and a smaller, "male" one).
2) Animals produce motile sperm with a flagellum tail, known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia.
3) Flowering plants have non-motile sperm within their spores, while ferns and certain gymnosperms have motile sperm.

Complete answer
Although all sperm cells have a head, body, and tail, they do not all have the same appearance. They can vary in form and size as a result of different irregularities, and other variations can be seen on any part of the cell (head, body, tail).
Healthy sperm will exhibit the following characteristics:
A smooth oval head - The smooth surface of a naturally shaped sperm's head resembles the outline of an egg.
The sperm head has a diameter of 2.5 to 3.5 um and a length of 4.0 to 5.5 um (um=micrometers). This yields a length-to-width ratio of 1.50 to 1.70.
They have a well-developed acrosome that covers 40–$70\%$ of the oval-shaped head.
A slender middle segment (body) that is about the same length as the head
A 45-micrometer-long thinner tail segment.
The flow of the sperm cell is provided by the tail. It whips and undulates so that the cell can fly to the egg. Following sperm deposition in the female reproductive tract, tail movement is suppressed until the sperm is transported within a very short distance of the egg.

Solution
Since the sperm must pass across the female reproductive system to reach the egg, it has a tail. The tail assists the sperm in going forward (like a snake) rather than in circles.

Note
1) The majority of the fluid in sperm is secretions from male reproductive organs.
2) The fluids contributed by the seminal vesicles account for roughly $60\%$ of the overall semen content.
3) Citric acid, free amino acids, fructose, hormones, phosphorylcholine, prostaglandin, potassium, and zinc are also found in sperm.