Why/how is a paperclip able to float on water?

Water surface tension

Explanation:

The water around the paperclip forms a kind of elastic surface, deforming, in which the clip can stay afloat.

This is because the molecules that are on the surface of the water, already in contact with the air, try to cling to those that are next to them and those that are immediately below.

If we added even if it were just a drop of soap in the water, the clip would go to the bottom, because the soap has the ability to decrease the surface tension of the water.

D. the training of infectious disease researchers.  

Explanation:

The source would help a reader get more knowledge about the training that clinicians and researchers get regarding infectious diseases. We can see that the reader will gain more understanding of the infectious diseases training in professionals because the email details the institution's name, which gives a general idea about their mission. Also, the message mentions the things that this organization does: improve infected patient care, training, and control of infectious diseases.

There is no mention in the email about the other options. The only thing that the message mention is the ISID's objectives, where the training of professionals regarding infectious diseases is one of them. In conclusion, the reader will gain more understanding about option d.