The diagram given below is that of a developing human fetus. Study the diagram and then answer the question that follows-

1. Label the parts numbered 1 to 3 in the diagram.
2. Mention any two functions of the part labeled 2 in the diagram.
3. Explain the significance of the part numbered 3 in the diagram.

1) Labeling the diagram:

1. The umbilical cord is a flexible tubular structure that connects the developing fetus and the mother in the uterus. It helps in the exchange of oxygen and nutrients and in the elimination of wastes.
2. The placental villi is a spongy disc-shaped structure that comprises numerous villi. It acts to increase the available surface area for the exchange of materials.
3. The amniotic cavity comprises the amniotic fluid that acts as a shock absorber by protecting the foetus from physical damage. It also prevents the dehydration of the foetus.

2) Function of part 2:

1. Part 2 is the placenta. It is the connecting link present on the maternal side in the uterus.
2. The placenta helps in the exchange of nutrients, antibodies, hormones, and oxygen to the fetus and the removal of nitrogenous wastes and carbon dioxide.
3. The placenta produces various hormones like hCG, progesterone, estrogen, corticotropin, thyrotropin, relaxin, etc.

3) Significance of part 3:

1. The amniotic cavity comprises a yellowish to clear fluid called the amniotic fluid. This fluid surrounds the fetus.
2. The amniotic fluid acts as a shock absorber. It also helps in maintaining a constant internal temperature.