Answer: The answer is C. Hope this helps :)
Explanation:
Pocket gophers<span> and </span>their<span> ecological cognates worldwide </span>have<span> profound impacts on </span>ecosystems<span>, from consuming vegetation to altering the soil physically. The rodents excavate vast burrow systems and deposit tailings in abandoned tunnels and on the ground surface.</span>
The high heat capacity of water prevents fish body temperatures from changing during the winter.
Striated muscles contain repeating sarcomeres of overlapping arrays of long, thin actin and thicker myosin filaments. Myosin filaments contains the myosin heads, which are enzymes that can bind to actin, split and make use of the energy from ATP. When muscle contraction starts, myosin heads bind to actin, change their configuration on actin, liberating the products of ATP hydrolysis and causing slide of the actin and myosin filaments. The action of the proteins troponin and tropomyosin on the actin filaments regulates vertebrae striated muscle contraction. The release of calcium ions from the sarcoplasmic reticulum is triggered by the nervous stimulation which causes depolarization of muscle membrane. Calcium ions bind to troponin and thus cause or allow the tropomyosin strands on the actin filament to move so that the part of the actin surface where myosin heads need to bind is uncovered. Contraction then occurs and only stops when the sarcoplasmic reticulum pumps calcium out of the muscle interior.
So basically, what triggers the uncovering of the myosin binding site on actin is the calcium ions binding to troponin and changing configuration.
<span>The celestial sphere is a coordinate system that uses the Earth as a reference. Declination indicates how far north or south from the celestial equator an object is. Right ascension indicates how far east or west from the vernal equinox an object is.</span>
