Answer:
Active uptake (which I think you mean active transport) is important when the concentration gradient is against that of a certain substance, so it doesn't cross the membrane through diffusion or passive transport. It is sometimes necessary if a substance needs to move across a membrane but can't do so due to electrical charge or that there is a substance on the other side of the membrane preventing diffusion.
Explanation:
Because it causes them to move, and so they weather that way. Buut the acid rain can leak into the rock and slowly break down the atoms, causing it to chemically weather faster. Also, just regular water/rain can wash away some covering sediment.
Hello there.:D
Which is an adaptation?A. A dog is trained to catch a ball.
B. A person learns how to do math.
C. A rabbit has fur that blends in with snow
D. A bird breaks its wing in an accident.
C. A rabbit has fur that blends in with snow
Answer is A
Firstly axon must reach the threshold level and then depolarisation occurs. Depolarisation phrase means sodium enters and potassium leaves the axon . Choice C can't be because main idea is the entering of sodium ions.
Answer:
C
Explanation:
The meninges are the membranous tissues that cover the spinal cord and the brain, providing support and protection to these organs. They are of three layers.
A) The Dura mater
B) The arachnoid mater
C) The pia mater
The Dura is the outermost meningeal layer and lies directly under the vertebral column bones and skull. The subdural space is the space between the Dura mater and the Arachnoid mater.
The Arachnoid mater lies in the middle of the Dura and Pia mater. Under the Arachnoid layer is the subarachnoid space which contains the cerebrospinal fluid. The cerebrospinal fluid acts as a shock absorber and a cushion to the brain and spinal cord.
The Pia mater lies under the subarachnoid space and directly on the spinal cord and brain and is highly vascularised.
