Final answer:
In the second trimester of prenatal development, the fetus grows significantly, becomes active, and the pregnant person can feel its movements. The placenta takes over nutrition, waste management, and hormone production, supporting the fetus until birth.
Step-by-step explanation:
In the second trimester of prenatal development, which spans from weeks 13 to 28, significant changes and developments occur. During this period, the pregnant person may experience an increase in energy and a cessation of early pregnancy symptoms like nausea and vomiting. Weight gain becomes more notable, and around week 20, the fetus's movements can be felt by the mother. The fetus grows to approximately 30 cm (12 inches) and becomes more active, with all organs and structures further developing. A critical change during this trimester is the placenta taking over the vital functions of nutrition and waste management, as well as the production of hormones such as estrogen and progesterone, from the now-degenerating corpus luteum. The placenta will support the fetus until delivery.