Answer:
The sodium-potassium pump is an active transporter because it needs to move sodium and potassium ions against the concentration gradient.
Explanation:
You have to think of it as outside vs inside the cell.
Outside the cell, you have 5mM K and 150mM Na. Inside the cell, you have 100mM K and 10mM sodium. Without the transporter then the ions would go from greater concentration to lower concentration. Energy keeps the ions going from the way they would naturally happen.
Yes Darwin’s theory of natural selection
Answer:
Photosynthetic organisms (plants and/or phytoplankton) are at the bottom of the food chain.
Explanation:
The crayfish have its nerve cord on the ventral side rather than on the dorsal side. The ventral side is under the Crayfishes' exoskeleton, as opposed to the dorsal side where the exoskeleton is . If it is attacked it will be from the dorsal side and the nerve cord would be snapped easier. The function of the nerve cord is that if it gets attacked by a predator they will go for the top and it will still be able to move.