When water freezes(ice) it expands slightly
think ice cube tray, and why the amount of ice you get is more than the amount of water you put in<span />
The property of all ionic compounds that makes chalk particularly useful for writing on a chalkboard is : Hardness and Brittleness
Those properties make chalk leaves residues on the board every time friction happen between the chalk and the board
hope this helps<span />
Answer:
Valley lizard = Oviparous
Mountain lizard = Viviparous
Explanation:
In Darwin's theory survival of the fittest, he believed species adapt or change within their environment. So I believe lizards living in a valley would be more safe to lay their eggs but lizards living in the mountains would be viviparous because of the non-predicted and unsafe environment which could harm the better chances of development of the offspring.