1 example of partially permeable please

Plasma Membrane

Explanation:

It allows water and some mineral salts to pass,but it doesn't allow large sized salts to pass in plant as it has small pores.

Cause ;

A cross-bridge forms between actin and the myosin heads triggering contraction. As long as Ca++ ions remain in the sarcoplasm to bind to troponin, and as long as ATP is available, the muscle fiber will continue to shorten.

Effect;

During a concentric contraction, a muscle is stimulated to contract according to the sliding filament theory. This occurs throughout the length of the muscle, generating a force at the origin and insertion, causing the muscle to shorten and changing the angle of the joint.