Temperature and oxygen level
Answer:
Flatworms are beings that do not have a heart, veins, arteries, capillaries, hemolymph, or some type of circulatory fluid. Their circulation occurs between cells or intercellularly and they are responsible for transporting substances by diffusion from cell to cell.
Explanation:
Flatworms are considered multicellular eukaryotic organisms. This implies that in their cells they have a cellular nucleus, in which the DNA is contained, structuring the chromosomes. Likewise, they are made up of several types of cells, each one specialized in a specific function. They lack a structured circulatory system as such. Because of this they do not have specialized structures such as a heart or blood vessels, however, the circulation of certain substances is established between their cells. This is done thanks to the diffusion process. Substances pass from one cell to another through this process.This does not apply to all flatworms, since in some species of bog and digenae there is a certain organization and some very small conducting vessels known as the endolymphatic system, the which forms a kind of plexus in the parenchyma.It should also be noted that some species do not even have a digestive system, being the digestive tract the one in charge of digestive functions and the distribution of the nutrients they receive.
Answer:
3. Antibody-independent pathways of complement activation rely on complement components that directly bind to microbial surfaces.
Explanation:
There are three pathways of complement activation:
- The classical pathway.
- The alternative pathway.
- The lectin pathway.
The classical pathway is triggered by binding of C1 either to the pathogen surface or to antibody bound to the pathogen.
The alternative pathway is triggered by the spontaneous hydrolysis of soluble C3 to C3(H₂O) and initiates eventual deposition of C3 convertase on microbial surfaces.
The lectin pathway is triggered by the binding of mannose-binding lectin or ficolins to carbohydrate residues in microbial cell walls and capsules.
Answer:
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Explanation:
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