What must occur to a shopping cart at rest in order to make it roll forward

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

If assuming tasting ptc as a simple gene trait,what other genotype would you select to put in this missing genotype box that could result in this phenotype

1) strawberry plants typically reproduce by making runners, which are miniature versions of themselves, that grow off of the roots and stems of the parent. this type of vegetative reproduction is known as a) pollination. b) fragmentation. c) binary fission. d) vegetative propogation.