Fact 1: Thyroid hormones increase the rate of metabolism in cells throughout the body. Fact 2: Hyperthyroidism is an overactive thyroid gland . Given the two facts above, what can increase the rate of metabolism in cells throughout the body?

OPT:
(1). hyperthyroidism.
(2). sweating.
(3). an electric stove.
(4). Power plants.
(5). electricity.
(6). mitosis.
(7). haploid.
(8). smoking cigarettes.
The answer is:
(1).