Flatworms have no need for circulatory and respiratory systems because they are able to actively diffuse oxygen through their skin and their body layout is such that they do not need to transport oxygen in order for it to get to their cells.
CD4 and CD 8 are molecules present on the surface of T cells where they interact with major histocompatibility (MHC) Molecules.
CD4 and CD8 improve T cell signalling by attaching to MHC class II (CD4) or MHC class I (CD8) molecules on APCs.
- The association of CD4 with MHC class II significantly decreases the number of antigenic peptides necessary for T cell activation (5) and significantly boosts cytokine output by helper T cells.
The MHC molecules' wide polymorphism is their distinguishing trait.
- This polymorphism is crucial for T cell antigen recognition.
- A T cell detects antigen as a peptide bound by a specific allelic variation of an MHC molecule and will not identify the identical peptide bound by other MHC molecules.
- This type of T cell activity is known as MHC limitation.
Hence, the correct answer is option C
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C because you need sunlight to use photosynthesis
the correct answer is C) DNA contains the base uracil, while RNA contains the base thymine instead
Answer:
In anaerobic respiration, the end-products are ethanol and carbon dioxide in plants whereas the end-products are lactic acid only in animals.
Explanation:
