Which explains the basis of the biuret test?

sudan iii dye binds to lipids and changes color.

iodine fits into the coils of starch polymers and changes color.

a blue dye binds to protein and changes color.

under base conditions, copper ions bind to the amino groups of proteins and change color.

Which of the following descriptions of proteins are true? i. proteins can have different sequences of amino acids. ii. proteins can have different shapes. iii. proteins can have different numbers of amino acids. a. only i and ii are true. b. only ii and iii are true. c. only i and iii are true. d. i and ii and iii are all true. e. none are true statements

(drag each tile to the correct location.) categorize each term as something that is typical of a scientific theory, a scientific hypothesis, or both. - a tentative statement used to guide scientific investigations. - makes predictions about future events. - can be tested by many independent researchers. - based on observations of natural phenomena. - a well-established, highly reliable explanation.

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?