Which of the following statement(s) is/are true concerning the remodeling phase of wound healing?

b. The normal adult ratio of collagen is approximately 4:1 of type I to type III collagen.

d. The proteoglycans are responsible for the ground substance of the extracellular matrix

The transition from the proliferative phase to the remodeling phase of wound healing is defined by reaching collagen equilibrium. Collagen accumulation within the wound becomes maximal by two to three weeks after wounding. Although supramaximal rates of synthesis and degradation continue throughout remodeling, there is no further change in total collagen content. During the initial phase of wound healing, there is a relative abundance of type III collagen in the wound. With remodeling, the normal adult ratio of 4:1 (type I to type III) collagen is restored. The other important component of the extracellular matrix is the ground substance or proteoglycans. These substances are composed of a protein background with long hydrophilic carbohydrate side chains. The hydrophilic nature of these molecules accounts for much of the water content of scar. Scars never achieve the degree of order advanced by collagen in normal skin or tendons, but they do increase in strength for six months or more, eventually reaching 70% of the strength of unwounded skin.