The small intestine uses segmentation to mix chyme with digestive enzymes, increase its contact with the mucosa, and propel it forward through the digestive tract.

A. It increases both Na+ and K+ secretion: Aldosterone increases sodium (Na+) reabsorption and potassium (K+) secretion, but it does not increase the secretion of both ions.

B. It causes the urine to be more diluted. Aldosterone causes the urine to be more concentrated by increasing sodium reabsorption and potassium secretion.

C. It reduces Na+ reabsorption and K+ secretion. Aldosterone actually increases sodium reabsorption and potassium secretion, not reduces them.

D. It increases Na+ reabsorption and K+ secretion. Aldosterone promotes sodium reabsorption in the kidneys and increases potassium secretion, leading to more concentrated urine.

A. Triglycerides are a type of fat found in the blood, but they are not classified as "bad cholesterol."

B. High-density lipoproteins (HDL) is known as "good cholesterol" because it helps remove cholesterol from the arteries.

C. Low-density lipoproteins (LDL) are referred to as "bad cholesterol" because high levels of LDL can lead to the build-up of plaque in arteries, increasing the risk of heart disease and stroke.

D. Chylomicrons are lipoproteins that transport dietary lipids from the intestines to other locations in the body. They are not classified as "bad cholesterol."