The most logical answer sounds like D.
If it grows underwater then of course it's able to withstand water. <span />
Answer:
nitrogen gas and oxygen gas.
Explanation:
78% of earths atmosphere is made up of nitrogen and 21% is made up of oxygen.
The answer to this question is B.) China and India. China has apporiximently 700,000,000 people and India has approximently 500,000,000 people. Making up for 36% of the worlds population.
Answer:
B and C
Explanation:
B. In a given rock sample, the amount of Silicon-32 isotopes gets divided in half about every 170yrs.
This is the concept of half-life. Half life is the time take for half of a radioactive isotope to disintegrate. The shorter the half life the faster the isotope disintegrates.
From the question, we were told that it would take 170yrs for half of the isotope of Silicon to disintegrate to Phosphorus. This is the half life.
C. The half life can be used to determine the amount of Si-32 that has decayed from the time closure temperature was reached.
The closure temperature is very important in radioactivity. It is the temperature at which a system has cooled and there is no resulting disintegration of parent and daughter isotopes.
From first order kinetics, we know that the rate at which radioactive elements decay at any time is directly proportional to the number of radioactive atoms present. A knowledge of the half life helps to figure out the number of atoms that has decayed in time.
