What in tarnation does 12 mean

it is grammatically incorrect and is illegible to me and i can not answer it.

"urban sprawl, the spreading of large developments of housing and shopping areas around a city’s center, has many negative cultural and environmental effects. " (from your link)

so, your answer is: it has a negative effect on the environment, otherwise known as c~hope this mate. 

practicing good personal hygiene will reduce the risk of getting infected, and getting a disease.   dirt, germs and parasites can accumulate under the nails, so is important to keep your nails clean and trimmed.