Glutamate, gaba, and glycine are important because these are

Out of the following given choices;

a. the major excitatory neurotransmitters in the CNS. 
b. known to be solely inhibitory in the brain.
c. the predominant neuromodulators in the spinal cord. 
d. the most common neurotransmitters in the CN

The answer  is D. This is because the amino acids are the main synaptic neurotransmitters in the brain neurons. Glutamate is released by all brain neurons and has an excitatory effect. GABA and glycine have the opposite effect (inhibitory)

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.