What is half-life?(3 points)

Question

Responses

The geologic age of a fossil, or a geologic event or structure expressed in units of time, usually years. Also known as actual age.
The geologic age of a fossil, or a geologic event or structure expressed in units of time, usually years. Also known as actual age.

Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.
Two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.

The time required for half of the atoms of a radioactive substance to break down into other elements.

Answer 1

The correct response that defines half-life is:

The time required for half of the atoms of a radioactive substance to break down into other elements.