Twins produced when a single egg is fertilized are called ______________twins. Twins produced from two eggs ovulated at the same time are called ______________ twins.

A. Small intestine; small intestine: Both amino acids and monosaccharides are absorbed in the small intestine, and fatty acids are also absorbed in the small intestine, where they are reassembled into triglycerides and incorporated into chylomicrons.

B. Small intestine; liver: Amino acids and monosaccharides are absorbed in the small intestine, but fatty acids are absorbed in the small intestine, not directly in the liver.

C. Stomach; small intestine: Amino acids and monosaccharides are absorbed in the small intestine, not the stomach, and fatty acids are absorbed in the small intestine, not the stomach.

D. Stomach; large intestine: Amino acids and monosaccharides are absorbed in the small intestine, and fatty acids are absorbed in the small intestine, not the stomach or large intestine.

A. Small intestine, particularly the ileum, contains Peyer's patches, which are abundant lymphoid tissues in the mucosa and submucosa. These structures are part of the immune system, protecting the body from pathogens in the digestive tract.

B. Stomach: While the stomach has some lymphoid tissue, it does not have as much as the small intestine, specifically the Peyer's patches.

C. Large intestine has lymphoid nodules, but it does not contain as much lymphoid tissue as the small intestine.

D. Esophagus has very little lymphoid tissue compared to the small intestine, as its primary function is to transport food rather than participate in immune defense.