Final answer:
In childhood, brain development mainly involves increases in neuron size and the number of dendrites and synapses. Neurogenesis does occur, but it is limited in scale and effect. The most significant changes are the formation and pruning of neural connections.
Step-by-step explanation:
During childhood, the brain undergoes significant growth and development. While neurogenesis (the formation of new neurons) can occur in the adult brain to some extent, the primary developments in the brain's growth during childhood involve increases in neuron size and, more critically, the development of dendrites and synapses. The process known as blooming involves the rapid formation of neural connections in the early years, followed by pruning, where less used pathways are eliminated to enhance the brain's efficiency. In adolescence, the brain does not increase much in size but rather in complexity, with an increase in the number of folds in the cerebral cortex and myelination.
The correct answer to the question is E. neuron size and number of dendrites and synapses.