Why are there semi lunar valves in arteries

The seed coat's most important function is to provide a) a nonstressful environment for the megasporangium. b) the means for dispersal. c) dormancy. d) a nutrient supply for the embryo. e) desiccation resistance.

Prompt compare the three types of volcanic mountains in terms of shape, type of eruption, and the minerals that make up the volcano

Guard cells control which event? the growth of plants capture of solar energy gas exchange in leaves water absorption in roots