Coordination and regulation of body activities in mammals are achieved by the

Analyze the question The question asks which systems work together to coordinate and regulate body activities in mammals. "Coordination and regulation" is the key phrase.

Explain the concept Mammals have two main coordinating systems:

1. Nervous system (nerves): The brain, spinal cord and nerves carry electrical impulses. The responses are fast and short-lived, for example pulling your hand away from a hot object.
2. Endocrine system (hormones): Glands such as the pituitary, thyroid, adrenal glands and pancreas release chemical messengers into the blood. The responses are slower but longer-lasting, for example growth, metabolism, and blood sugar control through insulin.

Together, these two systems integrate and control everything the body does.

Solution: checking each option

• A. Nerves and muscle: Muscles are effectors. They carry out responses and do not coordinate anything. Wrong.
• B. Nerves and hormones: Both are coordinating systems, and they work together. Correct.
• C. Nerves only: This leaves out the endocrine system, so it is incomplete. Wrong.
• D. Hormones only: This leaves out the nervous system, so it is incomplete. Wrong.

Answer: B. nerves and hormones

Exam tip Remember "N-H" for coordination: Nerves + Hormones. Muscles and glands are effectors, meaning they carry out the response, while nerves and hormones do the coordinating. If a question says "coordination," look for an option that has both the nervous and endocrine systems.