Answer:
The return of blood to the heart is assisted by the action of the skeletal- muscle pump. As muscles move, they squeeze the veins running through them. Veins contain a series of one-way valves, and they are squeezed, blood is pushed through the valves, which then close to prevent backflow.
The cuticle decreases water loss and stomata assist gas exchange. The plants from wet habitats must have a comparatively large number of stomata and thin cuticle. The plants existing in dry habitats must have comparatively few stomata and thick cuticle.
Answer:
In general, a scientific law is the description of an observed phenomenon. It doesn't explain why the phenomenon exists or what causes it. The explanation of a phenomenon is called a scientific theory
Explanation:
The answer's D. Cretaceous.
Conidia are fungus spores. Macrocnidia means that the fungus spores are complex and large. Microconidia are fungus spores that are smaller.
