Answer:
A radioactive (unstable) phosphorus isotope is made to replace a nonradioactive isotope of phosphorus in the molecule
Explanation:
Phosphorus has both unstable (radioactive) and stable isotopes. In any compound that contains phosphorus, the phosphorus atom present may be either a stable isotope of phosphorus or an unstable isotope of phosphorus.
However, if the molecule contains a stable nonradioactive isotope of phosphorus, it is possible to convert this isotope in the molecule to the unstable radioactive isotope by carefully carrying out exchange reactions in which the phosphorus isotope replaces the nonradioactive isotope in the molecule.
This is usually done in order to create radioactive tracers which are used to study chemical reactions and biochemical processes.
Answer: alternative A.
Explanation: In this case, we will consider people that already have had a heart attack. In this specific group of 1,000 people, 236 exercised regularly and had gone through this situation.
We can infer that 23.6% of people who exercised regularly have experienced that by dividing 236/1,000= 0.236= 23.6%.
If 236 people exercised, 1,000-236=764 didn't exercise regularly prior to their heart attacks, so 74.6% were considered to be sedentary.
If there's 0.236 chance out of 1 to exercise and still have a heart attack compared to 0.764 out of 1 to be sedentary and have the same experience, we can divide both ratios to compare them, so 0.236/0.764= 0.3089.
Alternative A claims that people who exercise have around 0.5 chance of having heart attacks compared to people who don't. Since our ratio resulted in 0.3089, we consider this number the closest to 0.5. Alternative <u>B is absurd because in order for people who exercise to have 2x the risk compared to people who don't, the number of people who exercised and went through that must be 2x bigger than people who didn't</u>. Alternative <u>C doesn't apply as well, because we already verified that the chance people who exercise have a heart attack equal to 23,6%. </u>
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Because there are other liquids in your body it passes through and it adds to the amount of water.
Food web stability is most dependent on the number of connections among species.
Answer:
ecological succession in this area will washout and more danger to many citizens on that area.
