Leukotrienes are part of a class of biologically active compounds that occur naturally in the white blood cells or the leukocytes. These compounds functions in the pathogenesis of inflammation. They trigger the contraction of the smooth muscles located in the bronchioles. Excess amounts of this substance is a cause of the inflammation during asthma and in allergic rhinitis.
Answer:
D. Mass extinction events separate the three eras from each other
Explanation:
The Phanerozoic represents an eon, and it is the most recent one. It is further divided into three eras, Paleozoic, Mesozoic, and Cenozoic. The division between the tree eras is because of mass extinction events. The Paleozoic and Mesozoic era are divided by the Permian-Triassic mass extinctions. The Mesozoic and Cenozoic are divided by the Cretaceous-Paleogene extinction. The Cenozoic era is still in existence, as there hasn't been a mass extinction of a magnitude big enough so far.
Answer:
have an open circlitory system
Explanation:
Answer:
Humming birds are one of the most interesting animals in the world. Some of them are so small that they are often mistaken for bumblebees. They're known to dive underwater and quickly dive right out while flying, and they eat more than they weigh to prepare their travel across an entire ocean non-stop. On top of all of this, they can be pretty rare depending on where you live, and they're really fun to watch.
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