A fern is a seedless vascular plant because it has vascular that transports water, nutrients, and food throughout the plant. Tissue

Spores

Stems

Seeds

i believe it would be the lungs.

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.

unicellular organisms, like bacteria, are able to perform all life functions within one single cell. multicellular organisms need many different types of cells to carry out the same life processes. each of these special types of cells has a different structure that it perform a specific function.