Which statement correctly explains why hair appears the way it does?
a. gray hair is the result of hormonal action altering the chemical composition of melanin.
b. perfectly round hair shafts result in wavy hair.
c. kinky hair has flat, ribbonlike hair shafts.
d. air bubbles in the hair shaft cause straight hair.

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.