Well there's a couple reasons why. First, the land itself can become “tired" and less fertile<span>. This is because the same type of </span>crop<span> planted repeatedly in the same area keeps draining the land of the same nutrients needed for that plant's growth. Pest can also plant their nest near the crop if the farmer continues to plant the same crop in the same place.
Which is the reason why things such as "crop rotation" exist to keep things fresh, and prevent what I described above from happening.</span>
Answer: D) The effect of gravity on an object
Explanation: We're not talking about mass, we're talking about weight. Weight is measured by the force of gravity on a object. For examples, you might be 100 pounds on Earth but 12 pounds on the moon.
Answer:
Part A: 36 MBq; Part B: 18 MBq
Explanation:
The half-life is the time it takes for half the substance to disappear.
The activity decreases by half every half-life
A =Ao(½)^n, where n is the number of half-lives.
Part A
3.0 da = 1 half-life
A = Ao(½) = ½ × 72 MBq = 36 MBq
Part B
6.0 da = 2 half-lives
A = Ao(½)^2 = ¼ × 72 MBq = 18 MBq
1) same amount of carbon atoms.
That is why it is still called butane and butene.
but- always signifies 4 carbons
