The correct answer is - No.
The Cambrian explosion is a term used for the big and rapid diversification of the animal species, but it is not the period in which the animal life started. The animal life started in the period between 620 and 550 million years ago, in what is known as the Vendian Period. In the Vendian Period, the first complex animal organisms appeared, started to develop and evolve, though it is not a period where there was a high diversification of the species. The later Cambrian Period provided better living conditions, and that resulted in a so called ''explosion of life'', which resulted in much more new species developing and evolving.
It keeps the water in the plant, so it keeps the water from evaporating and killing the plant
I think that since it lives on the ocean floor, at the deepest of the ocean. So anyway, the fin on the Eurypterids is still necessary but not that much, since they live on the ocean floor. Their movements mostly on the ocean floor. So fin would not help them "stick" to the floor. Also there are still gravity acts on the Eurypterids and the feet would help them move faster. Hope this helps.
Answer:
4.Cell wall protects the cell whiles organelles are found in the cell itself which is having the cell wall
