Sully works as a geologist in the southwestern united states. he plans to choose an unstable isotope to find the absolute age of a rock sample. which two aspects must he consider before making his choice? two answers 14 points 1 there should be a sufficient amount of the selected isotope in the rock. the isotope should be one that decays at a very fast rate. 2 the isotope must not be found in any neighboring rocks. 3 the half-life of the isotope must be long enough to capture the age of the rock. 4 there should be more than one unstable isotope in the rock.

3. The half- life of the isotope must be long enough to capture the age of the rock. and

4. their should be more than one unstable isotope.

In radioactive dating proces, the parent isotope is in unstable state which undergoes decay process to give stable  daughter isotopes. Half-life is the amount of time it takes for half of the parent isotopes to decay. The  rock dating requires a long lived parent isotope so that it can capture the exact rock age.

One rock when get decayed in the daughter isotope other will be available identify the age.

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.