During a study session about evolution, one of your fellow students remarks "The giraffe stretched its neck while reaching for higher leaves, its offspring inherited longer necks as a result, which statement is most likely to be helpful in correcting this students misconception? a) characteristics acquired during an organisms life are generally not passed on through genes
b) spontaneous mutations can result in the appearance of new traits
c) only favorable adaptations of survival value
d) disuse of an organ may lead to its eventual disappearance

Mouse liver cells were homogenized and the homogenate subjected to equilibrium density-gradient centrifugation with sucrose gradients. fractions obtained from these gradients were assayed for marker molecules (i.e., molecules that are limited to specific organelles). the results of these assays are shown in the figure. the marker molecules have the following functions: cytochrome oxidase is an enzyme involved in the process by which atp is formed in the complete aerobic degradation of glucose or fatty acids; ribosomal rna forms part of the protein-synthesizing ribosomes; catalase catalyzes decomposition of hydrogen peroxide; acid phosphatase hydrolysis monophosphoric esters at acid ph; cytidylyltransferase is involved in phospholipid biosynthesis; and amino acid permease aids in transport of amino acids across membranes. a) name the marker molecule and give the number of the fraction that is most enriched for each of the following cell components: lysosomes; peroxisomes; mitochondria; plasma membrane; rough endoplasmic reticulum; smooth endoplasmic reticulum.