Troponin, a major protein in thin filaments, is a globular protein with three polypeptide subunits. which of the following is not a function of the troponin? a) one subunit binds to calcium ions. b) one subunit binds tropomyosin and position it on actin. c) one subunit binds to potassium ions. d) one subunit attaches troponin to actin.

The correct answer is C.

Explanation:

Troponin have 3 subunits called Troponin C, Troponin T and Troponin I:

Troponin C is responsible for binding calcium ions. C might be a reference to calcium.

Troponin T is responsible for binding tropomysoin. T might be a reference to tropomysoin.

Troponin I is respobsible for binding actin.

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.