HHH Why does 95% of the people in GENERATION Z want this. Married at 18, kids at 20, die of drug overdose at 30

Which scientific design has both practical limitations and limitations due to scale? studying the effect of bleach on the growth of mold spores exposing cultures of duckweed to different intensities of light observing the replication of dna molecules with a hand lens using colored marbles to model a cross between two colors of rabbits