I need a argument to: Differences in the structure of protein molecules affect how they connect to other protein molecules. This can result in different traits

Ineed to know why d is the correct answer asap

Ascientist separates a population of mice into two groups. what would most likely increase the rate of speciation in this population. a. teach the two groups different tricks b. allow the two groups to breed with each other c. put the two groups in different environment d. have the two groups live in identical ecosystems

How can an organ, such as the lungs, work for multiple body systems?