Answer:
I'm pretty sure it's the first answer.
Gamma rays are not used for communication.
-- We have no safe way to generate them.
-- We have no cheap way to detect them.
-- We have no way to impress information on them (modulate them).
-- They're dangerous.
Otherwise they're ideal for communication.
Keynote is great for presentation
Put a code or security system on or a very secure password
Hope this helps...
Answer:
A. Document camera
Explanation:
Document cameras, which are also known as visual presenters or visualisers, digital overheads, or docucams. They are real-time image capture devices for displaying an object to a large audience. Just like an opaque projector, a document camera is able to magnify and project the images of actual, three-dimensional objects, as well as transparencies. They are, simply put, high resolution web cams, that is mounted on arms so as to facilitate their placement over a page.
This makes it easier and convenient for a teacher, lecturer or presenter to write on a sheet of paper or to display a two or three-dimensional object while the audience watches.
In Theory, the document camera can be used to display all objects.
Gwen only needs to place her photo under a document camera and deliver her speech while the image will be displayed for the class.
