The first three strong radio sources, discovered by Reber in the 1930s and 1940s, included all of these EXCEPT Group of answer choices supernova remnant. distant galaxy. globular cluster. galactic nucleus

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

when it gains or loses electrons

i think it would be 5

in most common fires, oxygen is needed for an oxidation reaction to takes place. the combination of oxygen with any element as fuel can create fire and combustion will occur especially if wood, light materials and other combustible things are combine with oxygen.