Why have questions about mantle convection been so difficult for scientists to answer lately?

Select the correct text in the passage. the moving continents affect all subsystems on earth. which sentence identifies a potentially negative consequence of shifting continents? the supercontinent pangaea began to break up about 175 million years ago. [during this process, more coastline was exposed as the landmasses separated]. [the rearrangement and displacement of these huge landmasses resulted in the diversity of plants and animals we see on earth today]. [the movement of the plates sometimes leads to earthquakes and tsunamis]. however, over the long course of earth's history, their effects are usually minimal. in oceans, the plate movements usually lead to seafloor spreading. [seafloor spreading often results in the formation of underwater ranges of mountains].

What was the great rift valley formed by

(10 points) 1. cone 2. rectangle 3. triangle 4. circle 5. cylinder a. perpendicular cross section of a pyramid b. perpendicular cross section of a cylinder c. parallel cross section of a sphere d. shape created when a rectangle is rotated about the y-axis e. shape created when a right triangle is rotated about the y-axis