A client has experienced excessive losses of bicarbonate and has subsequently developed an acid–base imbalance. How will this lost bicarbonate be replaced?

The kidneys will excrete increased quantities of acid.

Explanation:

The kidneys will excrete excess H+ ions in the blood (remember H+ ions are responsible for acidity) until the acid-base balance is restored in the blood. Bicarbonates, on the other hand, will be aggressively  reabsorbed by the renal tubules as the excess H+ are being excreted.

The acid base balance is mainly determined by the quantities of H⁺ and HCO₃⁻ ions in teh blood. These ions come from the dissociation of carbonic acid formed when carbon dioxide from tissues is dissolved in blood plasma.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.