What kind of bonds link amino acids to form the basic sequence of a protein? a. disulfide b. peptide c. hydrogen d. noncovalent e. ionic?

Ivan is looking at a cross section of a stem taken from a vascular plant. he sees two different types of vascular tissue: the xylem, which is closer to the center of the stem, and the phloem, located around the xylem, closer to the outside of the stem. how do these two structures work together in a living plant?

Which example best describes a reflex action? a. eating food when hungry b. coughing when the throat is irritated c. bending down to lift a heavy object d. going for a walk outside

Which of the following is the scientific term for an organism that makes its food from inorganic materials? a. autotroph b. heterotroph c. embryotroph