A Which best describes primary data?
O data collected by professional archivists
Odata collected by the researcher
data used only by the researcher
data used by many people

Data collected by the researcher

Explanation:

The data collected by the researchers is written first or primarily. Then that data is kept with the professional archivists and so on.

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).

apprenticeships are formal, paid, long-term training programs that provide valuable classroom instruction coupled with on-the-job training for skilled, high-paying jobs.