Pls help me with this test!!

There are fewer than 100 naturally occurring elements in the universe, but there are millions of different unified substances. explain how this can be true.

Match the following terms and definitions. 1. species that are adapted to live in equilibrium at carrying capacity population density 2. population growth that reaches equilibrium and carrying capacity population 3. death rate mortality 4. birth rate k-selected 5. a group of interacting individuals of the same species within the same geographic area natality 6. the number of organisms living in a particular area logistic growth

Explain how the parts of the peripheral nervous system work with the central nervous system to produce a response to the stimulus