Heart rate is controlled by the two branches of the autonomic (involuntary) nervous system. The sympathetic nervous system (SNS) and the parasympathetic nervous system (PNS). The sympathetic nervous system (SNS) releases the hormones (catecholamines - epinephrine and norepinephrine) to accelerate the heart rate.
Answer:
Consequences of the widespread use of plastic materials can be an increase in levels pollution and the overflowing of landfills because most plastics are non-biodegradable and can take a very long time to disappear unlike things like paper which are biodegradable.
121 C at 15 PSI for 15 minutes.
Answer:
Explanation:
The scientific method
Make an observation.
Ask a question.
Form a hypothesis, or testable explanation.
Make a prediction based on the hypothesis.
Test the prediction.
Iterate: use the results to make new hypotheses or predictions.
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Half life is the time taken by a radioactive isotope to decay by half of its original mass. In this case the half life of carbon-14 is 5500 years.
The original mass is 30 g and the new mass is 3.75 g.
New mass = Original mass × (1/2)^n, where n is the number of half lives;
3.75 = 30 × (1/2)^n
1/8 = (1/2)^n
n = 3
Thus, the time taken will be; 3 × 5500 = 16500 years.
