Answer:
Larynx
Explanation:
The Larynx is an organ of the body located at the anterior of the neck. It is also called the glottis or the voice box. The larynx is the air passageway or structure that connects to the trachea, it directs air into the lung and hence aids breathing. This organ is responsible for sound production, breathing and helps to prevent pulmonary aspiration. The larynx comprises of the vocal folds which plays an important role in speech and singing; in making of sounds the larynx muscle regulate the tension and the length of the vocal folds in order to tune the tone and the voice pitches.
Calcium ions are stored in the sacoplasmic reticulum. Sarcoplasmic reticulum plays an important role in storage and also acts as a release site for calcium. When calcium is released by the sarcoplasmic reticulum into the muscle it binds to the troponin, thus causing the tropomyosin to shift from the face of the actin filament to which myosin heads need to bind to produce a contraction.
Answer: D)organisms that possess overall characteristics best suited to their environment
Explanation: organisms that can evolve best suited have a better chance of life for example if put a rat in the arctic it will die to the cold but a paler bear will survive.