Several hours following death the muscles of the body stiffen, a condition commonly referred to as rigor mortis. what is the cause for the stiffened muscles? myosin heads are not attached to actin filamentsmyosin heads are attached to actin filamentsactin degenerationmyosin degenerationbuild up of atp due to lack of circulation

Myosin heads are attached to actin filaments

Explanation:

During the process of muscle contraction, myosin heads are attached to actin filaments. ATP is necessary for their release and for the muscle relaxation.

In rigor mortis, myosin heads continue binding with the active sites of actin proteins. This occurs because after death, there is no production of ATP and consequently, the muscle is unable to relax until further enzyme activity degrades the complex.

the relative atomic mass of an element is the mass of one atom of that element, relative to 1/12th of the mass of a  1212c atom. to convert to an absolute mass in kg, it is necessary to multiply by  1.661×10−271.661×10−27.

the relative atomic mass is roughly equal to the number of neutrons, plus the number of protons, in the nucleus of the atom.

for elements with more than one stable isotope (different types of nucleus with different numbers of neutrons but the same number of protons), the quoted mass is usually the average mass, weighted by the relative abundance of the different isotopes.