Answer:
The correct answer is A. Brief stressors lead to changes in cytokine production.
Explanation:
Cytokines form an important group of proteins that act as mediators of communication between living cells. They can exert their action in a paracrine way (between neighboring cells within the same tissue), or endocrine (between cells located in different tissues). The imbalance on the immune system that stressful events exert is an increase in the production of pro-inflammatory cytokines and their associated spectrum of age-related syndromes and diseases. Proinflammatory cytokines are soluble mediators that promote and mediate inflammatory processes, the following stand out: interleukin 1 (IL-1) is involved in the regulation of the immune process and inflammation; interleukin 6 (IL-6) that also serves as a link between the endocrine system and the immune system; and Tumor Necrosis Factor (TNF), which has the ability to destroy certain cell lines and initiate the cascade of pro-inflammatory cytokines and other mediators.
In traditional plant breeding, new varieties are developed either by selecting plants with desirable characteristics or by combining qualities from two closely related plants through selective breeding.
answer: a,
High-altitude environments present a number of physiological challenges for endothermic animals, as they are characterized by a lower partial pressure of oxygen (<span>) and lower ambient temperatures compared to low-altitude environments at similar latitudes. The reduced </span><span> at high altitude results in reduced oxygen loading in the lungs such that the blood may not carry a sufficient supply of oxygen to the cells of respiring tissues (</span>Bencowitz et al. 1982<span>; </span>Bouverot 1985<span>; </span>Turek et al. 1973<span>). This reduced level of tissue oxygenation can impose severe constraints on aerobic metabolism and may therefore influence an animal's food requirements, water requirements, the capacity for sustained locomotor activity, and the capacity for internal heat production.
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Answer:
Earth's tilted axis causes the seasons. Throughout the year, different parts of Earth receive the Sun's most direct rays. So, when the North Pole tilts toward the Sun, it's summer in the Northern Hemisphere. And when the South Pole tilts toward the Sun, it's winter in the Northern Hemisphere
Explanation:
