In an eight–cell embryo of an organism, the cells of the upper tier are aligned directly over the cells of the lower tier. which organism is it likely to be?

Which mantle is under the crust the upper mantle or the lower mantle i think it's upper let me know if i'm right

Which of the following statements about c4 carbon fixation is not true? a c4 carbon fixation is an adaptation for plants exposed to high light intensityb. c4 carbon fixation occurs in more plants than c3 carbon fixation.c c4 carbon fixation is more common in areas of high temperatures than c3 carbon fixation.d. c4 carbon fixation occurs in the inner cells of a leaf rather than the entire leaf.

Long-period comets come from the oort cloud particles in earth’s atmosphere material from the asteroid belt the kuiper belt