Make wood ducks mate only with female wood ducks. They produce make and female wood duck offspring that can mate only wi Ty other wood ducks. These facts indicate that wood ducks

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.

you know they are heterozygous for a trait because they have it as jj or jj.