Which of the following statements regarding sarcomeres is not true?
a. sarcomeres are overlapping thin and thick filaments.
b. the sarcomere is a subunit found on the myofibril.
c. sarcomeres extend from one m line to the next m line.
d. the position of the myofilaments in a sarcomere give it a banded appearance.

Sarcomere are overlapping thin and thick filaments.

Explanation:

Sarcomere is the structural unit of the skeletal muscle. Sarcomere is responsible for the striations of cardiac and skeletal muscle.

Sarcomere is a segment present between the M lines. The arrangement of thick and thin filament in the myofibril is responsible for the dark and light bands of sarcomere. A-band region of sarcomere contains both the thick and thin filaments of actin and mysoin proteins of the muscle cell. Thus, sarcomere are not the overlapping  of thick and thin filaments.

Thus, the correct answer is option (A).

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers