Problem 6 - Biology: The Dynamic Science

Question

In mammalian development: a. the morula develops into a trophoblast. b.the chorionic villi allow the blastocyst to move down the oviduct. c. the allantois takes over the work of the amnion. d. the pharyngeal arches transform into the pharynx, larynx, and nasal cavities. e. prolactin stimulates parturition.

Step-by-Step Solution

Answer

Statement a is false, statement b is false, statement c is false, statement d is true, and statement e is false.

Step 1: Checking statement a

The morula actually develops into a blastocyst, not a trophoblast. So, statement a is false.

Step 2: Checking statement b

The chorionic villi are not involved in the movement of the blastocyst down the oviduct. This movement is facilitated by cilia in the oviduct and by muscular contractions. Chorionic villi, instead, allow for nutrient exchange between the mother and the embryo. Thus, statement b is false.

Step 3: Checking statement c

The allantois does not take over the work of the amnion. Instead, the allantois becomes part of the umbilical cord, while the amnion remains as a protective covering for the embryo. Thus, statement c is false.

Step 4: Checking statement d

The pharyngeal arches do indeed transform into parts of the face and neck, including the pharynx, larynx, and nasal cavities. Therefore, statement d is true.

Step 5: Checking statement e

Prolactin stimulates milk production, not parturition. Therefore, statement e is false.