1)
scientists routinely explore whether two different animal species have evolved from a recent common ancestor. is the least useful technique to with this determination.
a) analysis of strands of dna
b) comparisons of bones and muscles
eliminate
c) comparisons of items eaten for food
d) studies of embryos during development

doctors i believe if i'm wrong sorry

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.