Which of the following is not a way that nonnative organisms are introduced to new aquatic ecosystems related to commerce? a. cargo ship hulls b. recreational boats c. escape from aquariums d. migration

D. migration

Aqua culture is the phenomena for rearing fish and other aquatic organisms with high commercial value for food production. Non- native organisms are added in an ecosystem in order to raise their number keeping in mind the availability of food for them. For creation of new aquatic ecosystem cargo ship hulls, recreational boats, organisms escape from the aquariums can be useful as these methods are non- natural and they are disturbing the original productivity and stability of ecosystem by introducing nonnative organisms to new aquatic ecosystem. But migration is a natural phenomena in which non-native organisms move to other habitat in search for food and habitat required for survival.  

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cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!