A. <span>Exposure to an antigen
Exposure to viruses and antigens led to the foundation of modern vaccination. Vaccination introduces an antigenic material that helps the ability of the immune system to adapt a specific pathogen, therefore leading to a long-term immunity.</span>
Answer:
C. Protein
Explanation:
Proteins contain C, H, O, and N.
Most notably, they contain an R group (aka a side chain), which is different for each for amino acid. The R group is symbolized by the letter R in the image.
Eukaryotes
Nuclear
Divide
Organelles
Membrane
Evolved
Molecules
Brane
Regulating
Active
Nucleus
Endoplasmic
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Answer:
The main difference between relative dating and radiometric dating is that relative dating is the method used to determine the age of rock layers according to their relative depth whereas radiometric dating is the method used to determine the absolute age with the use of decaying products of the natural radioactive. Also, absolute dating is more precise than relative dating because it tells the exact age of the fossils. Both are ultimately based on the fossils found in the strata.
Species evolve independently possibly due to geographical isolations or behavioural isolations.
Geographical isolation includes the isolation of 2 groups of the same species. Since these 2 groups live in different locations, (e.g. a volcanic eruption resulting in a barrier between one side of an ocean and another side of the ocean), they will have different selection pressures in their different environments as well (e.g. one side of the ocean may have more sunlight and thus more underwater plantations than the other side of the ocean). Natural selection will eliminate those with disadvantageous characteristics (e.g. Fishes that only eat plants and nothing else on the side of the ocean with little plantations) with unfavourable alleles, and select for those with advantageous characteristics (e.g. Fishes are able to eat plants and other organic substances as well on the side of the ocean with little plantations) with favourable alleles.
Since the 2 groups have different selection pressures, natural selection will occur in different ways, selecting for and against different types of fishes with different types of alleles. Also, because of the barrier, they are not able to mate with each other, and there are no mixing of genes from one side of the ocean and the other side. They are genetically isolated. As genetic drift occurs over time, their gene pools become different from each other. Thus, they evolve independently.
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