Which of these pairs of elements is very likely to form a covalent bond?

Each pair of clay balls represents to planetesimals if each plane test molluscum pound of the same material and is separated by the same distance which pair experiences the greatest gravitational attraction

What best discribes the relationship between wavelength and frequency in a electromagnetic wave

The plant food contains nh4)3po4 what tests would you run to verify the presence of the nh4 ion and the po4 ion