Final answer:
To differentiate collagen fibers, silver impregnation is the most suitable staining method. Sudan Red dye will show staining in phloem sieve elements due to oil droplets. Connective tissue such as blood lacks collagen fibers.
Step-by-step explanation:
To differentiate collagen fibers from other fibers, the best staining method would be d. Silver impregnation. This technique specifically stains collagen fibers, making them visible as black fibers under a microscope, whereas other staining methods such as Wright's stain, Hematoxylin and eosin stain, or Sudan stain do not provide the same level of specificity for collagen fibers as silver impregnation does.
When analyzing a root that has been soaked in Sudan Red, a scientist observing sections under a microscope is likely to see the sieve elements in the phloem showing staining due to the presence of transported oil droplets. This observation stems from the fact that Sudan Red dye stains primarily waxy, hydrophobic materials. As for the type of connective tissue that lacks collagen fibers, the answer is a. blood, which is composed of cells, ground substance, and protein fibers, but not collagen fibers.