Final answer:
Normal accelerations before 32 weeks gestation include fetal movements starting from weeks 16-20, developments like coating with vernix caseosa, and notable changes in weeks 21-30 such as rapid weight gain, myelination, eyelash growth, and surfactant production in the lungs.
Step-by-step explanation:
Normal accelerations before 32 weeks gestation refer to the developmental changes and movements that a fetus goes through as it grows. During weeks 16-20, the fetus starts to make more powerful limb movements, often referred to as quickening. These movements become constrained over time due to limited space in the womb, causing the fetus to adopt the fetal position. Key developments during this period include the coating of the skin with vernix caseosa, marking the presence of lanugo, and the beginning of bone marrow erythrocyte synthesis. From weeks 21-30, fetal development continues with the onset of rapid weight gain, myelination of spinal cord axons, eyelash growth, the ability to open and close eyelids, and the production of surfactant in the lungs, which is critical for lung function after birth.