6:00 Pm is the answer i hope its right
Answer:
The correct answer is B. Worms move through changes in body structure caused by contraction of muscles compressing their watery fluid.
Explanation:
The hydroskeleton consists of a fluid-filled cavity, surrounded by muscles. The fluid pressure and the action of the muscles that border it, serve to change the body's shape and produce a movement such as digging or swimming. The successive contraction of various metamers, which are provided with bundles of circular and longitudinal muscle fibers, stretching and thickening parts of the body, allow it to move horizontally. Hydrostatic skeletons have a role in the locomotion of annelids, nematodes and other invertebrates. The hydroskeleton has similarities with the hydrostatic muscles.
With shorter necks, giraffe ancestors could not reach food-containing branches on tall trees. This resulted in the directional selection of giraffes with longer necks.
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Why is choosing a direction necessary? </h3>
It nearly appears obvious that the giraffe's long neck developed as a result of a lack of food in the lower branches of trees. The giraffe has a significant advantage because it is taller than any other mammal and can feed where few others can.
When compared to modern giraffes, the giraffe's ancient predecessors had a shorter neck. The plants that were lying at a higher level were inaccessible to them. Giraffe phenotypes have changed in various ways, and now have long necks to reach vegetation that is higher up. The extreme form is chosen above other features in directional selection. It was decided to choose the long-necked giraffe over the short-necked.
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There are approximately 12 transisthmian shrimps species, called sister species because they cannot interbreed effectively, in the Isthmus of Panama. It is believed that the closure of the Panama resulted to allopatric speciation of the shrimp population within the region.