Highly sensitive cells within the hypothalamus that react to changes in blood composition and cause the release of antidiuretic hormone (ADH) when appropriate are called.

osmoreceptors

Explanation:

Osmoreceptors are nerve cells (neurons) capable of detecting changes in the extracellular fluid (ECF) osmolality, i.e., in the amount of solute in free water within the ECF. Osmoreceptors are known to contribute to osmoregulation by controlling body-fluid balance. These sensory receptors are mainly localized in the hypothalamus of homeothermic animals where they detect variations in the osmotic pressure and stimulate the release of antidiuretic hormone (ADH) in blood in response to the increase in plasma osmolality.

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.