___________pass(es) from the maternal blood to the fetal blood. Fetal__________ pass(es) the other way.

A. High HDL: low LDL- High-density lipoprotein (HDL) is known as "good cholesterol" because it helps remove cholesterol from the arteries. Low-density lipoprotein (LDL) is known as "bad cholesterol" because it can lead to plaque buildup in arteries. A high HDL to low LDL ratio is considered healthy as it is associated with a lower risk of cardiovascular disease.

B. High LDL: low chylomicron- High levels of LDL are unhealthy as they increase the risk of plaque formation in arteries, which can lead to cardiovascular diseases. Chylomicrons are lipoproteins that transport triglycerides and cholesterol from the intestines to other parts of the body.

C. High SFA: low HDL- Saturated fatty acids (SFA) can raise LDL levels and lower HDL levels, leading to an unhealthy lipid profile and increased risk of heart disease.

D. High LDL: low HDL- High LDL and low HDL is an unhealthy combination because it increases the risk of cardiovascular disease due to higher potential for plaque buildup in the arteries.

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.