<span>Most children acquire a firm sense of gender identity by the age of three</span>
The correct answer is hypertonic
The correct answer is "<span>they can develop into most types of human cells".
Stem cells are cells that are undifferentiated to what function they may serve, depending on the tissue where it will develop in to. In the context of brain tissue implants, these stem cells can develop into brain cells or nerve cells or neurons which comprises the functional brain tissue; this is clinically significant as neurons are not capable of replacing themselves if damaged.</span>