In mice, single-gene mutations lead to obesity. The Ob gene codes for the protein leptin, a satiety factor that signals the brain when enough food has been consumed. The recessive ob- allele is a loss-of-function allele, so ob-/ob- mice do not secrete leptin into veins and capillaries; they do not experience satiety and therefore become obese. Leptin is...

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

the correct answer is sex-linked recessive.

i just took the test