Answer:
A substance that cannot be broken down into chemically simpler components is an element.
A substance that can be broken down into chemically simpler components (because it has more than 1 element) is a compound. Example: Water id a compound composed of elements hydrogen and oxygen.
Answer:
The nitrogenous bases present in DNA are purine (adenine or guanine) and pyrimidine (cytosine or thymine). Uracil is absent from DNA. Uracil is present as pyrimidine base in ribonucleotides which are components of RNA.
It is important to prevent soil erosion, because when soil is eroded is can lead to the <em>pollution of water</em> around it/ water that passes through it. Since water is one of the basic necessities of all life, polluted water and cause illness or death among humans, plants, or animals. As soil is eroding, the <em>quality of it is reduced</em>. This disturbs plant life and agriculture.
Ways to prevent soil erosion:
- crop rotation
- increased vegetation
- terracing
- strip cropping
Hope I helped ! :)
