Answer:
Thymosin
Explanation:
Thymosin is the term used to refer to a set of thymus polypeptide hormones that influence the maturation of T lymphocytes intended to play an active role in cell mediated immunity. Thymosin may serve as an immunotransmitter by modulating the hypothalamic-pituitary-adrenal and gonadal axes. It also helps to counteract the harmful effects of cortisol.
With each contraction cycle, actin moves relative to myosin. ... ATP can then attach to myosin, which allows the cross-bridge cycle to start again; further muscle contraction can occur. Therefore, without ATP, muscles would remain in their contracted state, rather than their relaxed state.
The first, second, and fourth statements are correct.
Organ. An organ is a system of tissues that work together on a larger scale to do certain jobs within an animal's body. Examples of organs are the brain, heart and lungs. Anatomy is an example of a biology specialty concerned with this level.