Answer:
Arthropods have a tough, non-living outer shell called exoskeleton, which protect their soft bodies while echinoderms have living endoskeletons, which develops within the deeper skin or body tissues and act as their protective covering.Explanation:
Answer: It is important to conduct many different experiments and estimates in a project for having as much statistic data as possible, because it is necessary to show proof on whichever project you are into. In order to avoid confusion, it's also possible to <u>organize data in Excel sheets/tables so it can be visually easier to interpretate</u>. <u>Gut instinct isn't enough to prove something wrong or righ</u>t, and <u>few data means higher probability of things going in ways other than the expected</u>.
The primary source of stem thickening in plants is the vascular cambium. It is a plant tissue located between the phloem and the xylem and in the root of a vascular plant. It is the source of secondary growth or the radial growth of the stem of a plant.