Platyhelminthes, like the flatworm seen here, do not have a respiratory system. all but one of the statements explains why this is possible. that is they a) are anaerobic organisms. b) live in a moist/aquatic environment. c) have a high surface area: volume ratio. d) have a thin body that facilitates diffusion throughout.

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.