The ability to communicate symbolically give rise to __________

As part of the criteria for panic disorder, at least one of the panic attacks has been followed by _____________ of persistent concern about having additional attacks and a significant change in behavior related to attacks.

Fill in the blank(s) with the appropriate word(s).

Also known as the brain's biological clock, the hypothalamus has a mere _____ neurons that regulate our levels of drowsiness

A) 200 B) 2,000 C) 20,000 D) 200,000