Factor favoring the transport across a cell membrane-

Ans. is 'c' i.e., High concentration gradient * Simple diffusion refers to diffusion of molecule across the membrane following a concentration gradient or chemical gradient, but without the help of any carrier protein.* The rate of diffusion depends on following factors : -A) Rate of diffusion is directly proportionatei) The concentration (chemical) gradientii) Cross-sectional area of the membrane through which diffusion takes placeiii) Lipid solubility of the substanceB) Rate of diffusion is inversely proportionatei) The thickness of diffusion membraneii) Size of the particleiii) Charge or polarity of substance* So, simple diffusion is favoured by small size, lipid solubility and absence of polarity (non-polar substance) and charge (neutral molecule) through a thin, large membrane where the concentration gradient is more.