Answer:
The revision of the passage that best connects ideas and adds variety is - Running is inexpensive, yet you can run on a treadmill. You can run outdoors, however, you should not run on icy roads.
Explanation:
The sentences given are short and simple. But when it comes to fusing the meaning and making it sound better, linking words are used. Here, using the words "yet" and "however" all the short sentences are joined to form one sentence which sounds well and offers the correct meaning at the same time. The flow of the sentence is better. There is less amount of jarring and stopping which helps it to connect ideas and add variety to the joined sentences.
Oh there have been plenty.
STI's for example including HIV (human Immunodeficiency virus) has definitely boosted the awareness of caution and avoiding risky behaviors in both sexual terms and reducing exposure to bodily fluid via blood in work, or IVDA (intravenous drug abuse) needle sharing.
Additionally potentially dangerous and very infectious diseases like the Flu have put an emphasis on the very basic disease prevention of washing ones hands, covering your sneezes, wearing face masks during exposure, and getting vaccinated as well.
And these are merely two examples of how hundreds of disease shaped out infection control protocols and norms.
Oysters contain the most zinc, compared to any other food. there are 32mg of zinc in 6 raw oysters.
hope that helps :)