The answer would be the ozone layer. <span>A layer of ozone in the upper atmosphere absorbs </span>UV radiation<span> and </span>prevents<span> most of it from </span>reaching<span> the </span>Earth<span>. ... This means that more </span>ultraviolet radiation<span> can pass through the atmosphere to the </span>Earth's<span> surface, particularly at the poles and nearby regions during </span>certain<span> times of the year.
I hope that this helped you! Good luck. :)</span>
In contrast to compact bone, spongy bones does not contain true Haversian systems( tiny tubes that form a network in bone and contain blood vessels) but consist of an irregular lattice of thin plates of bone called trabeculae.The spaces between trabeculae are filled with marrow. The cells of the red marrow are responsible for producing blood. Within trabeculae lie lacunae which contain osteocytes.<span> Blood vessels from the periosteum penetrate through to the spongy bone, and osteocytes in the trabeculae are nourished directly from the blood circulating through the marrow cavities.</span>
C) Primary Producer. The producers are what make the food chain. Without them there would be no primary consumers. And without primary consumers there would be no secondary consumers.
i am not 100 on this but i thinkk it is B