Why must there be a continuous flow of water across the gills of fish?

Water passes across the fish's gills and the gills extract oxygen from the water.

Yes, fish have gills. YES FISH HAVE GILLS the gills are used for the output(takeing the water away) of water after the fish has extracted(picked out) the oxegyn from the water.

Gills of the fish help it breath under water.

Fish pass water over their 'gills' the gills extract oxygen from the water.

Fish use gills to breathe under water. A fish intakes water from its mouth, oxygen is absorbed through gills and water is thrown out.

Fish use gills to extract oxygen from the water passing over the gills.

Fish have gills, as they swim water passes over the gills and extract oxygen from the water.

A fish! Fish are the only animals with gills and most live in water.

Fish breathe with gills. Oxegen is in water. They breathe it in through their gills. They breathe it out through their mouth.

Fishes have gills when the water is moving on the gills than fish breaths and take oxygen from water.

No, only fish have gills.

Fish process the oxygen in the water through their gills. They suck in water and as they push the water out of their gills, the gills retain the air. This is why fish tank require pumps; to circulate the water and create oxygen.

nothing, anything with gills is classed as a fish. even if an elephant had gills and didn't even go in water, it's classed as a fish.

Fish take air from gills with water and inside gills there are small holes which seprate air from water.

fish have gills,fins,and live in the water. Sharks have gills

once the gills dry up, the fish will die of suffocation.

fish can live in water because they have gills.

Fish can absorb water by the gills

Fish gills are not suitable for air ventilation because, gills cannot function without water flowing through them. Gills are especially evolved and are an adaption of fish to breath under water.

Most organisms, except for some such as anaerobic bacteria, respire oxygen. Fish have gills, gills have the ability to take the oxygen out of the molecule H2O. Fish have gills, which filter out the oxygen from the water. However, they can't breath out of water. A fish doesn't have lungs, it has gills, so it doesn't breathe in water really. Fish breathe under water by using their GILLS to survive Gills pull oxygen from the water but they can't breathe out of the water because the other chemicals in the air.

Why do you live on land? Fish don't have lungs they have gills, when moving water is going through them the gills take the oxygen from the water and the fish breaths, no water = no oxygen = dead fish.

They are pulling the water they are swimming in across their gills. Therefore, freshwater fish are taking in a very dilute solution of salt water (> 0.9% salt) while saltwater fish are taking in a relatively concentrated solution of salt water (3-5% salt).

all fish have gills. they have gills instead of lungs, so they can breathe under water. Whales and dolphins do not have gills because they are mammals.

Gills are the things that help fish breath under water.

Gills to a fish are the equivalent of lungs in mammals. Without them the fish would not be able to breath in water.