The correct option is A.
The law of definite proportion states that a given chemical compound always contains its component elements in fixed ratio irrespective of the source they are obtain from.
For instance, water is made up of two atoms of hydrogen and one atom of oxygen. Water can not be formed in any other way. Combining the oxygen and the hydrogen in another ratio will give us another thing not water.
After 160 years, the activity level of the sample will be 0.5 curies.
<h3>What is half-life?</h3>
Half life of any radioactive waste is the half decay of that product.
The formula is 
Where, λ is 4 cruies
λ1 is 0.5 cruies
b = 40 years
Putting the values in the equation
Thus, the correct option is 160 years.
Learn more about half-life
brainly.com/question/24710827
#SPJ4
Erosion by water and earthquakes
Oxygen has a strong double bond which has more stability than the single co-ordinate bond in ozone, therefore more energy is required to break the O2 bonding than ozone, so the ozone molecule is more reactive than oxygen gas. ... The oxygen free radical contains two unpaired electrons in its valence shell.
Answer:
1
Explanation:
because there barely eating and there eating protien and healthy foods
