Q1. Synaptic signalling between adjacent neurons is like hormone signalling in which of the next ways?

A) It sends its signal molecules through blood. B) It sends its signal molecules quite the distance. C) It needs calcium ions. D) It requires binding of a signalling molecule to a receptor. E) It persists over a long period.

Q2. The plants and animals that live in the hot, dry ecosystems in Sonoran Desert are very different from those you see in Alaska, or in Costa Rica. Why might this be so?

Q3. A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble breathing. Why give an appropriate reason?