Has earth ever been covered completely by snow and ice

The model illustrates a process by which a substance is taken up by a cell

What is the difference between the conducting zone and the respiratory zone of the respiratory system? the conducting zone is a series of cavities and tubes that move air to the respiratory zone where gases exchange with the bloodstream. the conducting zone exchanges gases between the lungs and the alveoli and the respiratory zone is a series of cavities and tubes that move air to the conducting zone. the conducting zone moves oxygen into the cells and the respiratory zone takes carbon dioxide away from the cells. the conducting zone moves oxygen into the bloodstream and the respiratory zone takes carbon dioxide away from the bloodstream.

Many plants can reproduce asexually. which of these is an example of asexual reproduction in a plant? a. pine cones forming on a tree b. cross-pollination in a tomato c. roots sprouting from a potato d. night-blooming jasmine flowers