Do particles in a solid have thermal energy?

What is thought to have caused the mass extinction at the end of the cretaceous period?

The nervous system interacts with the endocrine system by a. using hormones as connections b. sending nerve impulses directly to glands c. using neuroendocrine cells as connections d. sending neurotransmitters directly to neurons

When the oxygen produced by photosynthetic plants in the water dissolves in the water, which of these is being formed?