How big is the biggest thing in the universe? a. 100 million miles across b. ten thousand decibels c. 80 million light years d. no one knows for sure

d. no one knows for sure

Explanation:

The universe is infinitely big. It goes on forever and ever, so no one knows what's in it. We might find something really big, but we'll never know if there's something even bigger out there.

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region 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.