Answer:
Flood barriers
Explanation:
Many towns in flood-prone areas are surrounded by flood barriers that are built to hold back rising water during seasonal highs.
- Flood barriers are water resistant walls that are used to prevent breaking water during a high period of inundation from their channels.
- They are usually vertical artificial structures which can be temporary or permanent.
- They help to hold or contain the flood water during the high season.
- These walls prevents flood plains and other nearby areas from getting flooded during the rainy season.
An ion has a positive or negative charge. While a covalent bond always has no charge, meaning it is neutral.
Answer:
Explanation:
Given that:
The Half-life of 
= 
is less than that of 
Although we are not given any value about the present weight of .
So, consider the present weight in the percentage of to be y%
Then, the time elapsed to get the present weight of = 
Therefore;
here;
= Number of radioactive atoms relating to the weight of y of
Thus:
--- (1)
However, Suppose the time elapsed from the initial stage to arrive at the weight of the percentage of to be = 
Then:
---- (2)
here;
= Number of radioactive atoms of relating to 3.0 a/o weight
Now, equating equation (1) and (2) together, we have:
replacing the half-life of =
( since 
)
∴
The time elapsed signifies how long the isotopic abundance of 235U equal to 3.0 a/o
Thus, The time elapsed is
Answer:
3rd statment
Explanation:
ray 1 and 2 are same vertical line
