In geology, a graded bed is one characterized by a systematic change in grain or clast size from one side of the bed to the other. Most commonly this takes the form of normal grading, with coarser sediments at the base, which grade upward into progressively finer onesI just learned about this in our rocks and minerals unit for science,
Physical is something you can have/ hold and mental is something in ur head that you can't see or hold.
Answer:
When calcium concentration increases during depolarization, it shifts the conformation of troponin and tropomyosin, and actin is able to associate with myosin. As calcium is taken up again by the sarcoplasmic reticulum the muscle cell relaxes.
