What type of organisms make up the first trophies level in most terrestrial food chains?

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

This part insulates the reaction chamber from the transfer of heat to or from the surrounding environment

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?