Read the statements given below and fill up the blanks with the correct words listed in the box.
deep, ductless, nutrients, thyroxine
(a) The meal that includes all __________ is a balanced diet.
(b) Insufficient production of __________ in the tadpoles leads to their incomplete development.
(c) Endocrine glands are also called __________ glands.
(d) After attaining puberty boys develop a__________ voice.
