<span>4 is a good answer. The question ‘can planting cover crops reduce erosion’ can be easily answered by creating a scientific study. You could create an experimental group where cover crops are planted and a control group where they are not, and measure the erosion of each group. </span>
The seven SI units are: kilogram, meter, second, kelvin,mole, ampere and candela.
Out of these seven, the one that will probably be part of the definition of a lumen is candela.
The luminous intensity of a light source is the the luminous flux emitted by that light source in a unit solid angle. The SI unit of luminous flux is lumen and the SI unit of luminous intensity is lumen divided by steradian [lumen/steradian] which is called Candela.<span />
Answer:
The nucleus (On the image, it's the sphere in the middle)
