Question

while eating lobster for dinner one night your friend asks what you think might happen if this marine invertebrate, which is normally isosmotic with respect to the surrounding seawater, were to be moved to a bay with a slightly lower salt concentration instead of being caught. you reply that, in order for the lobster to be isosmotic with respect to new environment,
multiple choice
it regulates its internal concentration of solutes to match that of its new environment.
it must move water in to match the solute concentration of its new environment.
it moves water in or out and regulates its internal concentration of water as needed.
it must move water out to match the solute concentration of its new environment.

Explanation:

An isosmotic organism adjusts its internal solute concentration to match the external environment. When the salt - concentration of the new environment is lower, the lobster will regulate its internal concentration of solutes to be isosmotic with the new surroundings. Moving water in or out mainly relates to volume regulation rather than achieving isosmotic balance in this context. The key is solute - concentration regulation.

Answer:

It regulates its internal concentration of solutes to match that of its new environment.