In one species of bird, there are three varieties of feather color. what is this an example of?

The question says, in one species of bird, there are three varieties of feather colour. What is this an example of? This is an example of condominance. Condominance is a type of dominance in which alleles of a gene pair in a heterozygote are fully expressed. This brings about an offspring that is neither dominant or recessive and the traits all get expressed.

Where are the options?

Answer : romans built laws to manage the pollution which was lead by smoke produced by the factories.

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.