The stomach contains hydrochloric acid and digestive enzymes.

Why doesn’t the stomach digest itself?.

 

The correct answer is choice D. Thrombocytes, also known as platelets, are tiny components of your blood that help with clotting. They are your body’s natural bandage to stop bleeding. When a blood vessel tears, thrombocytes stick together to form a clot, plugging the tear to stop bleeding.

Choice A is wrong because defending against infection is the function of white blood cells, not thrombocytes.

Choice B is wrong because transporting respiratory gases is the function of red blood cells, not thrombocytes.

Choice C is wrong because forming connective tissue is not the function of any blood cells, but of specialized cells called fibroblasts.

A normal platelet count for adults ranges from 150,000 to 450,000 platelets per microliter of blood. Any count above 450,000 or below 150,000 would be risk factors for platelet-related conditions.

The correct answer is choice B. Left ventricle. The left ventricle has the thickest wall because it pumps blood to the whole body through the aorta, which requires a lot of pressure.

The other choices are wrong because:

The normal range of wall thickness for the left ventricle is 0.6 to 1.1 cm. The normal range of wall thickness for the right ventricle is 0.3 to 0.5 cm.

The correct answer is choice B. Ear wax.

Ceruminous glands are specialized sweat glands that are located in the external auditory canal.

They secrete a waxy substance called cerumen or ear wax by mixing their secretion with sebum and dead epidermal cells. Cerumen helps to protect the ear from physical damage and infection.

Choice A is wrong because sebum is secreted by sebaceous glands, not ceruminous glands. Sebum is an oily substance that lubricates and protects the hair and skin.

Choice C is wrong because mucus is secreted by mucous glands, not ceruminous glands. Mucus is a slippery substance that moistens and protects the inner lining of various organs.

Choice D is wrong because keratin is not a secretion, but a protein that forms the structure of hair, nails and skin.

The correct answer is choice D. Carrots and squash. These foods are rich in carotenoids, which are orangey-red pigments that can accumulate in the skin and cause a yellowish or orangey discoloration. This condition is called carotenemia and is usually harmless and reversible by reducing the intake of carotenoid-rich foods.

Choice A is wrong because spinach and mustard greens are not high in carotenoids, but rather in chlorophyll, which is a green pigment that does not affect skin color.

Choice B is wrong because turnips and beets are not high in carotenoids, but rather in betalains, which are red or yellow pigments that are mostly excreted in urine and do not accumulate in the skin.

Choice C is wrong because rice and eggs are not high in carotenoids, but rather in protein and starch, which do not affect skin color.