What makes one appliance more efficient than another model of the same appliance?

He makes it efficient

HIGH EFFICIENCY

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.