A(n) [] is made of parts that work together.

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine

Which statement about relative potential energy of electrons is correct? a. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 2 s orbital of the second electron shell. b. an electron in the 2 p orbital of the second electron shell has more potential energy than an electron in the 3 p orbital of the third electron shell. c. an electron in the 3 p orbital of the third electron shell has more potential energy than an electron in the 2 p orbital of the second electron shell.

Which of the following molecules can be broken down into simple sugars? a. nucleic acid b. protein c. lipid d. carbohydrate