If a rat required a high rate of insulin infusion to maintain a specific blood glucose level, then you could conclude that it is:

The correct answer is: diabetic.

Explanation:

There are several species where diabetes can manifest, like rats, dogs, and humans. Diabetes Mellitus is a condition characterized by hyperglycemia (high blood sugar levels) and can lead to many complications that are life-threatening to the patients. This hyperglycemia can be caused by a variety of reasons, but they all include an insufficient reach of insulin (the most important hormone in blood sugar regulation) to the target organs - sometimes this occurs because the pancreas can't produce insulin, other times it's because the organs cannot receive it.

In patients in which insulin is NOT produced by the body, the administration of exogenous insulin is required for their survival - this seems to be the case with the rat mentioned in the case. This rat is an insulin-dependent diabetic.

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.