Biochemical limestone is when the calcium carbonate is locked into the fossil shells and skeletons of marine organisms.
But chemical limestone is when the calcium carbonate is in the form of calcite mineral crystals.
Hope it helps!
Macquarie River.
Margaret River.
Victoria River.
Wollondilly River.
Yarra River.
Mackenzie River Drysdale River.
Finke River.
Daly River.
I put more than five just in case. :)
Should probably look this up?
The circle with diameter of 24 means that 2

r = 24.
Solving for r, we get

r=24.
Dividing both sides by

, we get r=24/

.
The area of the full circle is

times 24 squared over

. The

being multiplied cancels out, meaning that 24 squared over

is the area of the full circle. 24 squared is 576, and dividing by 16 we get

as the answer.