The point where a motor neuron and a muscle fiber meet is known as the:

Correct Answer: D

Rationale: The neuromuscular junction is the synapse where a motor neuron contacts a muscle fiber, releasing acetylcholine to initiate contraction. Sarcoplasm is muscle cytoplasm, myofibrils are contractile components, and sarcomeres are within myofibrils, making 'Neuromuscular junction' the correct answer.

Correct Answer: B

Rationale: The radius and ulna, forearm bones, are part of the appendicular skeleton, which includes the limbs and girdles. They are long bones but belong to the appendicular division, not axial. 'Long bones' is a type, not a division, making 'Appendicular skeleton' correct.

Correct Answer: A

Rationale: Bones are living tissues, not inert structures. They contain cells like osteocytes, osteoblasts, and osteoclasts that maintain bone structure, repair damage, and regulate mineral content. Blood vessels and nerves within bones also support their living functions, such as growth and remodeling, making 'True' the correct answer.

Correct Answer: B

Rationale: The human body has three muscle types: smooth (involuntary, in organs), cardiac (involuntary, in the heart), and skeletal (voluntary, attached to bones). 'Rough muscle' is not a recognized category in anatomy; it may confuse with muscle texture but isn’t a type, making 'rough muscle' the correct answer for what is NOT a muscle type.

Correct Answer: D

Rationale: A long bone includes the diaphysis (shaft), epiphysis (ends), and medullary cavity (marrow space). The perichondrium is a cartilage membrane, not part of mature long bones (which have a periosteum instead), making 'perichondrium' the correct answer for what is NOT included.