Answer: 2) Vasoconstriction in most vessels
Explanation: Norepinephrine acts on alpha-adrenergic receptors in the vascular smooth muscles, causing vasoconstriction in most blood vessels. This diverts blood flow to critical organs like the brain and muscles, preparing the body for physical exertion.

The primary function of bile acids in the intestine is the emulsification of dietary fat, which aids in fat digestion and absorption.

Pepsin is the primary enzyme responsible for the breakdown of proteins in the stomach during the gastric phase of digestion. It is secreted as pepsinogen by the chief cells of the gastric mucosa and is activated by hydrochloric acid to become pepsin.

Elevation of aldosterone, in blood results in High 'Na' and high 'K' in urine resulting in acidic urine and body alkalosis

Answer: 4) Stimulation of mitochondrial oxidative phosphorylation
Explanation: Thyroid hormones, particularly T3, increase metabolic rate by enhancing the activity of mitochondrial oxidative phosphorylation. This leads to increased ATP production and overall cellular energy metabolism.