The answer is <span>insect and pest populations decreased.
</span>
DDT (dichlorodiphenyltrichloroethane) was used as an insecticide which is a substance used to kill insects. That resulted in decrease in insect and pest populations. It is a persistent and non-degradable insecticide, but as well organic pollutant readily accumulated to soils and consequently affects organisms.
Explanation:
For solid it could be melting into a liquid
for gas it could be Evaporating into a liquid
Answer:
1)the process being studied in the picture is transpiration I guess
3)the pot is covered with plastic sheet to trap the water (vapour) which is being evaporated