The four planets that orbit closest to the sun are best described as

Terrestrial planets

Explanation:

The first four planets which are closest to the sun are called as terrestrial planets. These terrestrial planets include Mercury, Venus, Earth and Mars. These planets are called terrestrial because they are earth like and are made up of either terrestrial substance such as rock, soil etc. or metals such as iron, manganese, etc. They also possess terrestrial features such as valleys, volcanoes and craters.

answer: decibel

explanation:

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.