Population refers to an array of organisms of the similar species, which thrives in a particular geographical region and interbreed. The three main characteristics of a population are density, size, and dispersion.
The density signifies towards how many organisms are thriving in a specific region. The size refers to how big a population is, and dispersion signifies towards the degree of spreading of the particular population.
A population of squirrels is preyed on by small hawks at maturity. the smaller adult squirrels can escape into burrows. the larger adult squirrels can fight off the hawks. after several generations, the squirrels in the area tend to be very small or very large. this is an example of disruptive selection. In disruptive selection, the extreme traits i.e., very small and very large sizes are favoured over intermediate trait i.e., average size.
A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to interact with a class II MHC-antigen complex
Importance of Class II MHC-Antigen complex
- CD4+ T cell-dependent immunological responses need antigen presentation restricted to MHC class II.
Professional antigen-presenting cells (APCs) perform a range of functions that are essential for the generation of an effective and specific immune response.
- Dendritic cells (DCs) investigate their surroundings and gather foreign antigens, such as those derived from bacteria or viruses, before activating CD4+ and CD8+ T cells to initiate adaptive immune responses against these antigens.
- The thymus' DCs and epithelial cells express (and also capture) a diverse set of self-proteins that contribute to both central and peripheral tolerance.
Recognizing the processes involved in the creation (and stability) of peptide-MHC class II complexes in APCs provides crucial information about T cellular metabolism including both normal and pathological settings.
Hence, the correct answer is option D
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It takes the muscle time to act once it receives a response from the nerves. It also takes time for the electric impulse to pass between gaps in the nerves (synapses).<span />
Virchow was correct when he concluded that cells arise from others cells, i.e., new cells are born through the division of one cell into two through the process of mitosis. The need for new cells continues throughout our lives, but it is greatest in early life. A fertilized egg divides into two cells, which give rise to four, and those give rise to eight, and then to 16, and 32, and 64, and so on. In a fully grown adult, of course, the rate of cell proliferation is much less, and under normal circumstances, cell division in an adult takes place only when signals indicate the need to replace cells that have been lost, damaged, or worn out. Basically when your young so is your cell and ask you get older they get stronger
