Why are guys penises shrinking

well, from gene prospective they get it from the mom's side of  the family

Explanation:

so it would be because of the grandfather. genetics, humans research, and a bunch of other things play into it.

so for now i'll say, that's life and science's fault

there is an explationation of this on a site called crash   course world history 1

in this scenario it would be the consumer demand as most influential in making the decision. the band members need to figure out where and from whom they will make the most money, in other words who out of the two consumer groups - football fans or car drivers - will spend their money, who is more likely to contribute to their cause and buy what they are offering.