Aplants has a genetics defeats that causes its leaves to dry out, becoming brittle and prone to injuries. the genetics defect most likely causes each leaf to lack a

Sufficient root system

Explanation:

Roots pull water and other nutrients from the soil to nourish the upper parts of the plant.  If a plant lacks sufficient root system, they start growing down. The leaves dry out and become brittle because they don't get enough water for photosynthesis.

Water is very important for photosynthesis because a low supply of water will directly affect the process of synthesis of food. Without food and nutrients, a plant cannot grow properly.

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.