Anjali's parents are divorced. Anjali spends weekends with his father and the rest of the week with his mother. In legal terms, this arrangement describes

Research that compares people of different ages who are similar in other important ways is called ______ research

Fill in the blank with correct word

_____ play(s) a critical role as a neurotransmitter that stimulates muscles to contract

A) Acetylcholine B) GABA C) Dopamine D) Endorphins