> Can fruits like water melon, cucumber etc replace water if the daily requirement for water isn't available ?
No. They can not replace drinking pure water. Each time you consume meat and plant material, it contains nutrients on their dehydrated form. Hydrolysis is need to breakdown these food products down to their simplest form for the body to utilize and transport them to different parts of the body.
When hydrolysis happens, the water molecules already present in the body are being used up by enzymes responsible for digestion on starch, protein, and fats. This is why consuming solid food products will make you more thirsty even you are not doing strenuous activities because water is still being used up to digest food.
"Water is very essential in the normal metabolism of humans and other animals" Yes, that is true.
"also in purifying the body system by removing the toxins in the body in form of uric acid in urine which makes it important to take a minimum quantity of water per day."
This part have no basis in science, it's just using scientific lingo.
"Can fruits like water melon, cucumber etc replace water if the daily requirement for water isn't available?"
And the meat of the question.
There are fruits and vegetables that have a very high percentage of water in them,
that is, relative to other.
Our own body is made up 60-70% of water.
Raw meat is as juicy as many fruits.
But you cannot just eat raw meat, somehow the water in it is not good...?
It's not about how much water a food have in it but about other characteristics of that food.
Meat is high in fatty acids and proteins, and to metabolize that, you need more water than that which is contained in the product itself.
So to answer this question.
You can substitute fresh water with some juicy fruits,
but not because of their high water %.
It's because to digest and metabolize those fruits and their nutrients, you don't need very much water.
The net positive water is higher.
Best of my knowledge ,its best to say supplement instead of replace. and yes, aside from fruits that have high quantity of fluids, there is also bit of water in almost everything that we eat.
Yes, they also contain water that can quench thirst. The disadvantage of fruit over water is that, those fruits during metabolism are broken down to their end product together with the water containing glucose, thus no holding up taste for a longer period
You ask can fruit replace water if the daily need for water is not available?
In my opinion, if indeed the situation is not there is water, then there is no other way to meet fluid needs. but fulfilling the need for fluids with fruits will not be able to fully meet the fluids in the body. and this cannot be done continuously, because the body will become dehydrated. Which means the body will experience a lack of fluid. and this will be dangerous for health.