Many biological catalysts hormones and receptor molecules are similar in that in order to function properly they must

(3) contain amino acid chains that fold into a

      specific shape

Explanation:

Biological catalysts, are substances that speed up the rate of biological reactions within the body of living organisms.

Hormones are chemicals found in the body of living organisms which are responsible for carrying physiological and behavioural regulatory messages between cells, organs or tissues.

Receptor molecules on the other hand, are substances that receive as well as transmit signals for cells in a biological system.

are proteinous in nature. They are made up of amino acids linked together by polypeptide bonds and folded into specific shapes depending on their functions.

From the options:

(1) interact with each other at a high pH

  (2) interact with molecules that can alter their

      specific bonding patterns

  (3) contain amino acid chains that fold into a

      specific shape

  (4) contain identical DNA base sequences

Option 3 is the correct answer.

to answer your question:

f(x)= a^x.  if x=0, f(x)=1  if x=1, f(x)=a  if x=1, f(x)=a^a