There are so many answers to that question. The uvula acts kind of like a door as well as any of the sphincters. The valves of the heart act like little doors also.
any door flap in the heart is a valve
A cat flap or cat door is a hinged flap set into a door, wall or window to allow cats to enter and exit a house on their own without needing a human to open the door, while offering a degree of protection against wind and rain entering the dwelling. Dog doors similarly exist for dogs.
A little doorlike flap is the valve.
A cat flap is at the bottom of a door and it is used for cats to get in and out of the house instead of having to open the door every time.
no
Answer:Yes a cat can have a cat-flap but the cat will most likely not use it.
Lift the rear door, Under the mat on the right side there is a little flap cut into the carpet. Under the flap there is a nut you put your tire wrench on and rotate with the wrench to lower it
Sir Issac Newton it was actually a CAT door-more a flap than a door
You can find dog door flaps in pet stores or, go to a hardware store and buy a stiff piece of plastic and then tear off the old door flap, use it as a pattern on the new plastic and cut out. Use a stable gun to attach to door.
there is a three dollar metal flap that u put on the door u must remove the flap and place the meatal spring and put the door bak on only four screws very easy
A cat flap is a small door cut into a standard house door that is covered with a flap that allows cats to enter and leave a house at will while keeping insects out and cool air or heat in. They come in various designs and styles, including models that record the time of day it was used.
There is non. Just push the flap and it pops out.
Push flap and springs open