The biotech company Medicago expresses viral genes in tobacco plants to generate flu vaccines. In the genetic code, the codons CAU and CAC both encode amino acid histidine. This ability to interchange multiple codons for a single amino acid is an example of how the genetic code is .

Degenerate.

Explanation:

The genetic code has following properties -

Out of these properties the Property of Degeneracy has been used in the situation mentioned in the question. Due to degeneracy of the genetic code, more than one codons can code for a single amino acid. Property of degeneracy in the code minimizes the mutational lethality.

materials water oxygen those are the things i can think of in this moment.

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.