Well, the density of the water is

so i believe that is what the question is asking for :)
Answer:
you need at least two out of the three to get any aenser
Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity.
I am attaching the rest of your question so it makes sense,
<span>
Since lasers are made from stacking light waves that add together into a larger wave due to CONSTRUCTIVE INTERFERENCE.
</span>
Then, <span>light waves have that constructive interference (from question #1) because they are emitted IN PHASE with each other.
This means that they arrive at the same point of space with the same characteristics and their effects do not cancel each other, but the opposite, their intensity increases.</span>
Answer:
a-
V= IR
9V = I ×( 12+6)
I = 9/ 18 A = 0.5 A
b
V=IR
240 = 6 A ×( 20 + R)
40 = 20 + R
R = 20 ohm
c
resultant resistance of the 2 parallel resistances= Ro
1/Ro = 1/ 5 + 1/ 20
1/Ro =( 20+5)/100
= 1/Ro = 1/4
Ro= 4 ohm
V=IR
V = 2A × ( 1+ 4 OHM)
V = 10V
d
equivalent resistance = Ro
1/Ro = 1/(2+8) + 1/(5+5)
1/Ro = 1/10 +1/10
2/10 = 1/ Ro
Ro= 10/2 = 5 ohm
V = IR
12V = I × 5Ohm
I=2.4 A