I think the answer is 3 and 4
The answer is B Because fat (myelin) acts as an insulator, membrane coated with myelin will not conduct an impulse.
A landform is a natural feature of the solid surface of the Earth or other planetary body. Landforms together make up a given terrain, and their arrangement in the landscape is known as topography. Typical landforms include hills, mountains, plateaus, canyons, and valleys, ... Oceans and continents exemplify the highest-order landforms.
