Which wave must have a medium to travel? A) light wave
B)compression wave
C) electromagnetic wave
D) ultraviolet wave

Urgent

Imagine you had to physically add electrons, one at a time, to a previously neutral conductor. you add one electron very easily, but the second electron requires more work. in your initial post to the discussion, explain why this is. also, what happens to the work needed to add the third, fourth, fifth, and subsequent electrons

How much energy must a refrigerator absorb from 225 g of water so that the temperature of the water will drop from 35°c to 5°c

Scientific models are based on current knowledge, which can limit their effectiveness when new discoveries are made.