Ultraviolet (UV) rays are invisible electromagnetic radiation from the sun and artificial sources, with wavelengths of 100–400 nanometers.

Representative government is a system in which citizens elect officials to create laws and make policy decisions on their behalf.

The intersection of two sets is the set containing all elements that are members of both sets, typically written with the ∩ symbol.

The heat of fusion is the energy required to change one gram of a solid into a liquid at its melting point without changing its temperature.

A spectrum in science is the spread of electromagnetic radiation arranged by wavelength or frequency.

Melanin is a natural pigment produced by cells called melanocytes that determines the color of your skin, hair, and eyes.

Hysteria is an outdated diagnosis once used for women’s unexplained symptoms. Today, these are understood as Functional Neurological Disorder (FND).

Half of 35 3/4 is 17 7/8, which equals 17.875.

A reactive intermediate is a short-lived, high-energy molecular species that forms during a stepwise chemical reaction and is not present.

A parallelogram with four right angles is called a rectangle. If it also has four equal sides, it is a square, which is a special type of rectangle.