Answer:
Most cells within planarians tend to be very close to their gastrovascular cavity, in addition to their external environments. Also, planarians have the ability for oxygen and carbon dioxide to diffuse through the cells on their body walls: this makes it unnecessary for these varieties of flatworms to need a dedicated bodily system.
I think the deficiency of dedicated respiratory and circulatory systems in Planarians does not cause a problem because none of their cells are far removed from the gastrovascular cavity or from the external environment. Planarians are free-living flatworms and form the class Turbellarians in the Phylum Platyhelminthes. Flatworms have three tissue layers, that is the ectoderm, mesoderm, and endoderm.
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Explanation:
It is due to agitation of the heart. This is the result of a blow in the area directly over the heart.
Food chains model energy flow through an ecosystem. Producers pump energy into an ecosystem from an environmental source, and this energy is then passed from one organism to the next.
Photosynthesis, in the chloroplasts of the cells
The best answer is B.
The endosymbiotic theory states that mitochondria and chloroplasts have striking similarities to bacterial cells:
1. they have their own DNA, which is separate from the DNA found in the nucleus of the cell.
2. Both organelles use their DNA for to produce many proteins and enzymes required for function.
3. They are both surrounded by a double membrane.
4. They reproduce just the way bacteria do, replicating their own DNA and directing their own division.
