Hi Dianna, nice to here from you again. The physical characteristics of your puppy are governed by a combination of genes that are contributed by each parent. Some of those genes are called dominant and their characteristic is always expressed. Some are called recessive and their characteristic is only expressed if the same gene is contributed by each parent. And still other genes are referred to as incomplete, meaning the physical characteristic is somewhere between each parents contribution. Your puppies appearance is the result of all these genes working together. I guess a simple way to look at is there can be one tall parent, one short parent and the offspring may either be tall, short or somewhere between.
As for your question about tearing up the pads this is a very common problem. Some alternative things to try include applying spray starch to the pad (tastes bad), you can also sparingly apply some hot sauce to the pad. There are many different types of chew deterrent sprays there is probably one of them that your puppies wont like. Many people resort to just using newspaper instead so at least it is not as costly.