Plz hw due tomorrow and its on european exploration (t-t)

Creation of an unnaturally uniform sample to represent a diverse populationcan be avoided by: a. including only willing b. asking another scientist for .c. choosing only identical participants.d. selecting individuals at random.

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation

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