Human skin becomes dry during winter, making it more prone to infections than during summer. how do the sebaceous glands protect the skin normally?

The meselson-stahl experiment demonstrated that dna replication is semiconservative. in the figure, semiconservative replication is illustrated by

The double bond between a carbon atom and two oxygen atoms (a molecule of carbon dioxide) has two characteristics. what are they? a.an ionic bond is formed between the oxygen and carbon atoms. b.four valence electrons are shared. c.two valence electrons are shared. d.valence electrons are shared between oxygen atoms.

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.