Answer:
D) four.
Explanation:
The two atria hold the blood that circulates away from the heart. The heart has four one-way valves, which open and close with each heartbeat. The tricuspid valve and the mitral valve are located between the atria and allow the blood to flow from the atria to the ventricles. Also you don't have to but mind marking Brainliest?
When the body is exposed to allergens or irritants, it will trigger the immune systems through different mechanism. However, the common pathway would result to multi-cellular inflammation, enhanced bronchial responsiveness, airflow obstruction and activation of immunological cell infiltration. Here, the inflammatory cell infiltrate are composed of varying amounts of eosinophils, neutrophils, and lymphocytes.
Moreover, T cells in the lung appear to orchestrate an immune response with a strong T helper type 2 (Th2) component when allergens drive the process.
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