Plants have cells that contain chloroplasts. why must their cells contain mitochondria as well?

Wind energy is plentiful in regions with vast open spaces it is a non polluting renewable resource what could be an economic factor that makes the use of this resource less feasible then non renewable resource even in such regions

Which represents a negative impact of technology

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