Lactase is a protein in the digestive tract that break down certain sugars found in milk. what is the main function of lactase?

Lactase protein acts as a digestive enzyme whose main function is to break down the lactose sugar. Lactose is found in milk and other dairy products.  Lactose sugar is a big molecule and thus it is difficult to metabolize it. Lactase breaks down the lactose into smaller molecules such as glucose and galactose, which are easily absorbed by the intestine.

the answer is "a.) well–developed vascular system."

explanation:

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.