Answer: A
Explanation:
A contour interval is a vertical distance or difference in elevation between contour lines. Index contours are bold or thicker lines that appear at every fifth contour line.
Windblown sand can wear away rock
Answer:
To break down the nucleus of an atom
Explanation:
Remember to change from one element to another, is necessary to add protons, neutrons and electrons,in most of the cases.
The take an electron from an atom you need certain energy, but they are in the outside part of the atom so is not as much energy as the one is necessary to take one neutron or proton from the inside part of an atom.
In this way, is a must to have a combination of pressure and heat to destabilize an atom and take some of this subatomic particles.
Answer:

Explanation:
= Concentration of stock solution
= Concentration of solution
= Volume of stock solution = 19 mL
= Volume of solution = 0.31 L= 310 mL
We have the relation


The concentration of the diluted solution will be 0.613 times the concentration of the stock solution.
Gold is found in pure state in nature but not the iron because gold is un-reactive metal, so it does not react with other element in normal condition but iron is reactive metal so it reacts with atmospheric oxygen in presence of moist (water) to form oxide.
Explanation:
I hope it'll help you.