Suppose there are 500 units of energy available at the producer level of the energy pyramid. approximately how many units of energy are available to the first-level consumer? a. 100 b. 5 c. 50 d. 1

Your answer would be c. 50. Remember the 10% rule. Multiply 500 times .10 and get 50

B. 50 units of energy are available to the first-level consumers.

TERTIARY CONSUMERS             0.5
SECONDARY CONSUMERS        5 
PRIMARY CONSUMERS              50
PRODUCERS                            500

Every unit of energy available at the producer level decreases on every level raised. The unit of energy goes down by 10% in every level. Thus, when the energy from producers, 500 units, goes up to the first-level consumer or primary level, it energy becomes 50.

It is called the medulla oblongata or people usually call it medulla. it is the lower half of the brain stem continuous with the spinal cord. 

Ascientist will use that to figure out how or why things are the certain way they are i hope this