The answer is: <span>larger horses have longer legs.
</span>The ancestors of horses lived in the forest, where they could hide from the predators. But, with the first steppes, they could be spotted by the predators. Horses had to adapt in order to survive. Thus, their legs became longer through time so horses could run faster to escape predators.<span>
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The chemical composition of bone is made up of collagen and calcium, which makes bones stronger
Answer:
The effects of climate change may be associated with the increased incidence of <em>V. vulnificus</em> infection
Explanation:
<em>Vibrio vulnificus</em> is a harmful bacterium that causes a serious disease due to eating contaminated seafood, which is the main cause of seafood-related deaths in the USA. <em>V. vulnificus</em> is naturally present in the flora of coastal waters around the world and this bacterium has been isolated from a variety of seafood (e.g.., fish, oysters, shrimp, etc). Epidemiologic studies have shown that the incidence of <em>V. vulnificus</em> infection has increased dramatically since 1996. During this same period, climate change has been responsible for the increase in salinity and temperature of the coastal waters (i.e., the natural habitat of this bacterium). In consequence, it is reasonable to suppose that the change in climatic conditions may be associated with the increased incidence of <em>V. vulnificus</em> infection.
Answer:
Having considered how an appropriate primary immune response is mounted to pathogens in both the peripheral lymphoid system and the mucosa-associated lymphoid tissues, we now turn to immunological memory, which is a feature of both compartments. Perhaps the most important consequence of an adaptive immune response is the establishment of a state of immunological memory. Immunological memory is the ability of the immune system to respond more rapidly and effectively to pathogens that have been encountered previously, and reflects the preexistence of a clonally expanded population of antigen-specific lymphocytes. Memory responses, which are called secondary, tertiary, and so on, depending on the number of exposures to antigen, also differ qualitatively from primary responses. This is particularly clear in the case of the antibody response, where the characteristics of antibodies produced in secondary and subsequent responses are distinct from those produced in the primary response to the same antigen. Memory T-cell responses have been harder to study, but can also be distinguished from the responses of naive or effector T cells. The principal focus of this section will be the altered character of memory responses, although we will also discuss emerging explanations of how immunological memory persists after exposure to antigen. A long-standing debate about whether specific memory is maintained by distinct populations of long-lived memory cells that can persist without residual antigen, or by lymphocytes that are under perpetual stimulation by residual antigen, appears to have been settled in favor of the former hypothesis.
