The owner, Sydney, had originally wanted a dog, so when she got Snow, she decided that she wanted to train her how to sit. So, when Snow was a kitten, she was given a cat treat (a fish treat) everytime she sat down when she was told to. This is known as a fixed ratio conditioning.
No matter where Snow is in the house, Snow will always sit when told because of the continuous conditioning that Sydney did.
Everyday at 12:00pm, Sydney will feed Snow 1/2 cup of food for lunch. This is known as a fixed interval schedule.
Snow however, loves food and sometimes can not wait for meal times so she will meow for people to give her food. Sometimes, a member of the family will give in and give her a treat to help her hunger. However it is only sometimes, with no predicable chance of them giving her food and is known as a variable ratio schedule.
The action of Snow meowing for a treat and the consequence of her occasionally getting a treat from the family was to snow, a positive reinforcement. However, because it was so random, it is not a problem that will severely increase her behavior. If her behavior was increased, then she will constantly meow and expect treats.