There are ________ primary teeth and __________ permanent teeth

Correct Answer: A

Rationale: Humans have 20 deciduous and 32 permanent teeth.

Correct Answer: B

Rationale: Bile salts emulsify fats for digestion.

Correct Answer: D

Rationale: The correct answer is D: oral cavity. The chemical digestion of carbohydrates begins in the mouth, specifically the oral cavity, where salivary amylase breaks down complex carbohydrates into simpler sugars. The enzyme amylase helps start the process of carbohydrate digestion before the food reaches the stomach. In contrast, the esophagus is not involved in digestion; the stomach primarily digests proteins with the help of gastric enzymes; and the duodenum is where further digestion of carbohydrates, fats, and proteins occurs with the help of pancreatic enzymes and bile.

Correct Answer: A

Rationale: The correct answer is A because assimilation involves the synthesis of new molecules from absorbed nutrients, requiring enzymes. Absorption, on the other hand, involves taking in nutrients through structures like microvilli and blood capillaries. Enzymes are essential for breaking down and building new molecules during assimilation. Blood capillaries and microvilli are necessary for absorption of dissolved nutrients, which are then utilized during assimilation. Therefore, enzymes are specifically needed for assimilation but not for absorption.

Correct Answer: B

Rationale: The correct answer is B: stomach. Gastric glands increase their secretory activity in response to the hormone gastrin released from the stomach. Gastrin stimulates the release of gastric acid and other digestive enzymes. The other choices, A: pancreas, C: liver, and D: duodenum, do not release hormones directly involved in regulating gastric gland secretory activity. Pancreas secretes insulin and glucagon, liver secretes bile, and duodenum secretes hormones like secretin and cholecystokinin, but none of these directly influence gastric gland secretions.