Answer:
the loneliness of the animals or the animals not wanting to go
Answer:D
Explanation: The pulmonary air sacs of birds only permit a unidirectional flow of air through the lungs. Unidirectional flow means that air is inhale and exhale through one trachea alternatively. This means the bird lungs only receive largely fresh air which has a high oxygen content during inhalation and do not receive fresh during exhalation. While air flow bidirectional in mammals.
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.
They replace the lost ions by active uptake through active transport
of ions from the surrounding waters. This is exhibited in freshwater fishes that
actively take in these ions through the gills. Most of the ions involved in osmoregulation in freshwater are those of Na+ and Cl-.
Working a side job at nights or on the weekends
