Answer:
Cell-mediated immunity develops through a network of interactions that results in defense against microorganisms that survive within phagocytes or other cells. The response is initiated by the recognition of intracellular microorganism antigen by T cells through the histocompatibility complex. In the CD8 response, only the target cell carrying the class I associated antigen can be lysed or induced to apoptosis. In another mechanism of the cellular response, CD4 + Th1 T cells activate, for example, cytokine-infected macrophages such as IFN. When a pathogen resists the effects of activated macrophages, chronic infection may develop.
The hormonal immunity response leads to the destruction of extracellular microorganisms and prevents or decreases the spread of intracellular cells by neutralizing, opsonizing and activating the complement system.
The precambrian era makes up about 90% of the earths history, but there was little to no living organisms at the time other than microscopic ones. The first eukaryotes were found in the cambrian period after the precambrian period, not only that but at the end of the precambrian era in the Proterozoic era there was a mass extinction of about 70-80% of all living organisms
If this is the picture you are talking about, the right answer is non-disjunction
Non-disjunction is the non-separation of homologous chromosomes at the time of cell division which results in the formation of ova or spermatozoa leading to an abnormality in the number of chromosomes of the egg thus fertilized by the spermatozoa.
The fertilized egg consists of either a single chromosome, what is called monosomy, or, conversely, three chromosomes, this is called trisomy. While naturally, the fertilized egg has a single pair of chromosomes.
Answer:
Adaptations of the alveoli:
Moist walls - gases dissolve in the moisture helping them to pass across the gas exchange surface. Permeable walls - allow gases to pass through. Extensive blood supply - ensuring oxygen rich blood is taken away from the lungs and carbon dioxide rich blood is taken to the lungs.
