The most successful reinforcement schedule to use after an animal has learned a new trick has been shown to be:
a)fixed-ratio
b) fixed interval
c) variable ratio
d) variable-interva

c) variable ratio

In operant conditioning, a variable-ratio schedule is a program of reinforcement where a response is strengthened after a variable number of answers. This program generates a constant, high rate of answering.

This schedule is practiced to enhance and sustain a uniform rate of particular responses. This program is best for sustaining behavior.

one would be wind another would be water density

the sphincter muscles at the end of the digestive tract is the anus.