Answer: The correct option is c. Segmentation evolved more than once in different branches of the cladogram.
Phylogenetic studies help to identify and understand evolutionary relationship between different life forms. It uses a diagram called as Cladogram to represent the branching of the evolutionary relationships. In cladogram studies each branching point tells a fundamental character of the evolutionary significance. Cladogenesis separates the gene pool by splitting into two or more than two separate pools each of which gives rise to one or more new species. Segmentation implies repeated parts and many animals consist of such repeated parts. Therefore, segmentation appears more than once in different cladogram branches.
해파리 (cnidarians) have a worldwide distribution. Despite most being harmless, some species may cause local and also systemic reactions. 처치 of 해파리 envenomation is directed at: alleviating the local effects of venom, preventing further nematocyst discharges and controlling systemic reactions, including shock. In severe cases, the most important step is stabilizing and maintaining vital functions. With some 차이점 between species, there seems to be evidence and consensus on oral/topical analgesics, hot water and ice packs as effective painkillers and on 30 s application of domestic vinegar (4%–6% acetic acid) to prevent further discharge of unfired nematocysts remaining on the skin. Conversely, alcohol, methylated spirits and fresh water should be 조심스럽게 avoided, since they could massively discharge nematocysts; pressure immobilization bandaging should also be avoided, as laboratory studies show that it stimulates additional venom discharge from nematocysts. Most 처치 approaches are presently founded on 상대적으로 weak evidence; therefore, further research (especially randomized clinical trials) is strongly recommended. Dissemination of appropriate 처치 modalities should be deployed to better inform and educate those at risk. Adequate signage should be placed at 바닷가 to notify tourists of the jellyfish risk. Swimmers in risky areas should wear 보호 장비.