<prompt> Microfilled composites cannot have a high filler load due to:Small size of filler particles which decreases the overall matrixMore surface area per unit volumeLow modulus of elasticityWear of opposing tooth structure caused by microfillers  <response>: Filler content of microfilled composite is 50-60 by weight. Because of the greater surface area per unit volume of these microfine particles they cannot be heavily filled.Reference- Sturdevant 6th ed P:218 