L Active transport IL Simple diffusion
lll Facilitated diffusion
IV. Osmosis
Which of the above type of transport moves molecules against a concentration gradient?
Your
ll and lV only
l only
ll only

l only

Explanation:

The movement of substances in living cells can either require energy (active) or not (passive) depending on the direction of movement across concentration gradient. Naturally, substances tend to move down a concentration gradient i.e. difference in concentration, which is from a region of high concentration of water to a region of low concentration. This is the passive type of transport, which does not require energy input. Examples are osmosis, simple diffusion and facilitated diffusion.

However, another type of transport exists in which substances move against the concentration gradient i.e. from a less concentrated region to a more concentrated region. In this case, energy input in form of ATP is required for this kind of transport to occur. This transport is referred to as ACTIVE TRANSPORT. Hence, the answer is I only.

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

pv=nrt

explanation: