Question

within a muscle fiber, troponin and tropomyosin are associated with _. myosin actin the sarcoplasmic reticulum need help? review these concept resources. rate your confidence to submit your answer. high medium low reading © 2025 mcgraw hill. all rights reserved. privacy center terms of use

Explanation:

Troponin and tropomyosin are regulatory proteins located on the thin - filament of muscle fibers. The thin - filament is composed mainly of actin. They play a role in regulating muscle contraction by controlling the interaction between actin and myosin.

Answer:

B. actin