Question 10

Hormones are chemical messengers that control growth, differentiation, and metabolism.

Hormones serve as the body's chemical messengers, playing a crucial role in regulating various physiological processes, including growth, differentiation, and metabolism in specific target cells.

A) Hormones

This option is correct because hormones are indeed the chemical messengers produced by glands that travel through the bloodstream to target organs or cells, where they exert their regulatory effects on growth, differentiation, and metabolism.

B) Neurons

Neurons are not chemical messengers; they are specialized cells that transmit nerve impulses. While they communicate through neurotransmitters, they do not directly control growth or metabolic processes like hormones do.

C) Glands

Glands are the organs that produce and secrete hormones, but they are not the chemical messengers themselves. Therefore, while glands are essential for hormone production, they do not fit the definition of chemical messengers controlling growth, differentiation, and metabolism.

D) Second messengers

Second messengers are molecules that relay signals received by cell surface receptors to target molecules inside the cell. They play a role in the signaling pathways initiated by hormones but are not the primary messengers that control growth or metabolism.

Conclusion

Hormones are the definitive answer as they directly function as chemical messengers influencing growth, differentiation, and metabolism in target cells. The other options either refer to related but distinct entities that do not fulfill the role of chemical messengers, thus affirming hormones as the correct choice.