Which of the following organisms have some strains that naturally carry a circular, 6.3-kb, 2-micron plasmid? A. Escherichia coli
B. Saccharomyces cerevisiae
C. Agrobacterium tumefaciens
D. Drosophila melanogaster

B

Explanation:

The correct answer for the organism with strains that naturally carry a circular, 6.3-kb, 2-micron plasmid would be Saccharomyces cerevisiae.

Most strains of Saccharomyces cerevisiae have been found to possess extrachromosomal elements in their nucleus. This extrachromosomal element is circular in nature and of about  2 microns and 6.3 kb without any known specific advantage or function.

Due to the simple nature of the yeast's plasmid, it has been a major source of study for the understanding and control of how replication works in eukaryotic organisms.

The correct option is B.

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.

a scenario where a cell may be needed to perform a form of endocytosis is when transporting large molecules. a scenario where a cell may be needed to perform a form of exocytosis is when releasing the large molecule from the cell.