Answer:
A. Molecular changes such as extracellular signals on extracellular ligands can result in quick changes in cell behaviour. One example is insulin. Upon insulin binding on the receptor on the cell membrane, the cell release GLUT4 transporters (for muscle cells) to increase uptake of glucose.
B. Slow changes in cell behaviour can be observed for other lipophilic hormones or intracellular receptors such as glucocoortoid or estrogen which reacts with receptors in the cells.
C. Insulin is required to maintain a constant blood glucose level and hence levels of insulin has to be mediated in correspondence to the blood glucose levels. Fast acting signalling is thus required for homeostasis of blood glucose levels. Where for such lipophilic hormones such as steriods, glucocortoid, these hormones tend to have a longer lasting effect and hence results in a slow change.
The correct option is C.
When a dog is afraid, its ears are usually pinned back to the head. A dog showing aggression will pulled its ear up and forward.
Other signs that a dog shows when it is afraid include: lowering of the head, wrinkling of the nose, curled lips that show many teeth, tucked tail, panting, etc.
Signs show by an aggressive dog include: head held high, curled lips only show the front teeth, tail is upright and stiff, no panting, etc.
The avian
kidneys are divided into units called lobules and as the two avian kidneys of
birds do their work or function, most of these birds excrete nitrogenous waste
known as uric acid from the blood, which reduces water loss but requires more
metabolic energy to produce nitrogenous waste.
