Which is a type of direct characterization?
“sally is so sweet. she always has a kind word or a candy in her pocket for the little children in the neighborhood.”
“steven hung back as the other boys got together at lunch. he smiled shyly as they passed him by, but he sat at a table alone.”
“suzee jumped and squealed when her father said they were going to the playground. she couldn’t sit still the whole way there in the car! ”

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.

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.