To answer this question, you need to know the concept of half-life, which is how a radioactive material decreases in mass over time.
The half life of U-235 is 703.8 million years. The first part of this problem is to find the scale factor. To do this, divide the time that has past by the half life, like this:

Now, take this scale factor and multiply it by the current mass, like this:

This number is what you add to the current mass to get the original mass. That is because the scale factor showed us that it was just over one half life. Since after one half life, the mass is cut in half, and this is over one half life, when we add to the original it will be a little over double. This equation illustrates the final addition:

I hope this helped you. Fell free to ask any further questions.
The answer is B- 124 degrees
Answer:
1. Reflex Conditioning
Explanation:
Conditioning is an aspect of learning where a stimulus works effectively in producing a response from an organism. This response becomes regular given the type of reinforcement that is administered to the organism. The reinforcement is usually a reward that is given to the organism.
This is what is observed in the woodpecker. The stimulus or reinforcement which proves effective in producing a continuous response from the woodpecker is the abundant supply of the birds favorite bugs. This reinforcement makes it possible for the woodpecker to become conditioned towards returning to the tree.
Answer:
1.32*10^23 molecules
Explanation:
sucrose formula: C12H22O11
molar mass: 12(12.01)+22(1.01)+11(16.00)=342.34g/mol
75.0 g C12H22O11 * (1 mol C12H22O11)/(342.34g C12H22O11)=0.219 mol C12H22O11
0.219 mol * (6.022*10^23)/mol = 1.32*10^23 molecules (three sig. figures)