Pond ecosystem considered as an open ecosystem because pond is always open . There is an interaction of pond with atmosphere , due to which it ecosystem becomes open.
Your nervous system quickly responds to the threat and sends a signal to your brain which causes your muscles/ body to react.
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The component of exercise that primarily strengthens the heart is aerobics. This heart strengthening exercises may include biking, running, walking, swimming, aerobic dances and a lot more that are sure to add strength to your your heart, lungs and stamina.
B. transport oxygen to tissues
<span>There are many different types of cells in multicellular organisms. Of course, depending upon the type of organism the overall number and different types will vary. In general though for mammals the broad classifications would include epithelial, endothelial, connective, smooth muscle, striated muscle, cardiac muscle, neuronal, glial, and many others. They can also be referred to based on their own embryonic development into 3 broad classes endodermal, epidermal, and mesodermal.
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