Ehrlich and raven hypothesized that if a new defensive trait evolves in a single plant species (or if a new trait to counteract a plant's defenses evolves in an herbivore species) the appearance of that trait could result in a period of species diversification. their hypothesis is also referred to as the hypothesis.

Coevolution

Explanation:

Ehrlich and Raven observed butterfly species and their host plants. Plant species had adopted a series of defence mechanisms against butterflies. In response the butterflies also evolved new traits to avoid these defence mechanisms.

In this way both butterflies and plants influenced each other's traits and they co evolved. The coevolution can lead to accumulation of lot of different characteristics which can lead to formation of new species and species diversification. Formation of new species will be observed both in plants and butterflies.

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.

burning fossil fouls really decrease the carbon in the atmosphere so b