If a drug caused a sudden release of large amounts of calcium in skeletal muscle, from which structure would the calcium come?

The correct answer will be option-sarcoplasmic reticulum.

Explanation:

The sarcoplasmic reticulum is the membrane bound endoplasmic reticulum of the muscle cell which stores a large amount of Ca⁺² ions.

The reticulum contains Calsequestrin- a calcium binding protein which binds around 50 Ca⁺² ions to itself and helps store more calcium. These calcium ions are released when the signals through T-tubules are carried to the reticulum which leads to the opening of the calcium channels.

Thus, sarcoplasmic reticulum is the correct answer.

b.final

geosphere and hydrosphere.

this is because the geosphere has to do with geological events, while the hydrosphere controls all water on earth.