The shielding of electrons gives rise to an effective nuclear charge, ZeffZeff, which explains why boron is larger than oxygen. Estimate the approximate ZeffZeff felt by a valence electron of boron and oxygen, respectively

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.

the answer would be c

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.