Everyday Science

Hands are generally considered the dirtiest part of the body because they frequently come into contact with various surfaces and contaminants, making them more prone to harboring germs compared to feet or face.

Photocopier machines produce ozone gas as a byproduct due to the high voltage corona discharge used in the copying process. This ozone is generated when oxygen molecules are split and recombine as ozone (O3).

A cantilever beam is a beam fixed at one end and free at the other. A diving board is a classic example of a cantilever beam, whereas a bridge, see-saw, and common balance do not fit this definition.

There are 16 ounces in one pound according to the standard US customary system of measurement, making option D correct.

Atmospheric air is held to the Earth primarily by gravity, which pulls the air molecules toward the Earth's surface, preventing them from drifting into space.

One kilogram is approximately equal to 2.20 pounds. This is a standard conversion factor used in everyday measurements.

Vitamin B complex is a group of water-soluble vitamins, unlike vitamins A, D, and K, which are fat-soluble. Therefore, Vitamin B complex is not fat soluble.

One ton (specifically a US ton or short ton) is equal to 907 kilograms approximately. This is the standard conversion used in everyday measurements.

An egg sinks in soft water because the water's density is less than that of the egg. In a concentrated salt solution, the density of the solution increases and becomes greater than that of the egg, causing the egg to float due to buoyant force.

The scientific study of caves is called Speleology. Haematology is the study of blood, Oology is the study of eggs, and Oneriology is the study of dreams, making Speleology the correct answer.