Why is it, when shoppers go to the grocery store, the store offers customers either plastic or paper bags to carry their groceries home in?

because plastic creates more pollution but is cheaper

In my opinion the word reason here is RENEWABILITY/SUSTAINABILITY.

Explanation: Renewability and Sustainability are both synonyms and can be defined as the ability for something to be produced or sustained for a long period of time without damaging the environment or without depleting a resource. Modern plastic shopping bags are increasingly recyclable or biodegradable. modern bags are made of vegetable-based bioplastics, which can decay organically and prevent a build-up of toxic plastic bags in landfills and the natural environment.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.