2. why would an imbalance in thyroid hormones have such widespread effects on the body?

Imbalance in thyroid hormones would have widespread effects in body.

Explanation:

Thyroid hormones are produced by thyroid gland which is located at the middle of the neck. Thyroid  hormones play a vital role in the metabolism of the body, brain development and brain growth. Main hormones produced by thyroid gland are T3 and T4. T4 levels are more in body than T3 levels.

If the thyroid gland fails to produce enough thyroid hormones it results in a condition called hypothyroidism. Fatigue, dry hair, weight gain, muscle cramps etc are the symptoms of hypothyroidism. Hyperthyroidism is the condition that arises due to the overproduction of thyroid hormones.

Symptoms of this condition are weight loss, sleeplessness, seizures etc.

passive transport is a movement of biochemicals and other atomic or molecular substances across cell membranes without need of energy input. unlike active transport, it does not require an input of cellular energy because it is instead driven by the tendency of the system to grow in entropy.

so, according to what that says, i believe it's hypertonic and hypotonic.

good luck!