Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics?
he proposed that plates carry parts of the seafloor.
he theorized that pieces of earth move for a limited time.
he suggested that the asthenosphere is broken into segments.
he observed seafloor cracks similar to existing cracks in the continents.

Which statement explains what happened to the agriculture economy in russia under communism

(1) which phrase describes an important agricultural change that occurred during the mississippian period? (a) first cultivation of wild grains (b) expansion of marsh elder farming (c) spread of corn agriculture (d) gathering of nuts and berries (2) which group of native americans use northwestern arkansas as it’s traditional hunting grounds? (a) osage (b) quapaw (c) woodland (d) caddo

One of the brightest comets of the 20th century was comet hyakutake, which passed close to the sun in early 1996. the orbital period of this comet is estimated to be about 30,000 years. find the semi-major axis of this comet’s orbit. compare it to the average sun-pluto distance and to the distance to alpha centauri, the nearest star to the sun, which is 4.3 light-years distant.