The body is too worn down to deal with the stress and leaves the body vulnerable to injury.

#Question id: 56

#Unit 1. Molecules and their Interaction Relevant to Biology

Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?

#Question id: 57

#Unit 1. Molecules and their Interaction Relevant to Biology

A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge.

#Question id: 58

#Unit 1. Molecules and their Interaction Relevant to Biology

A covalent chemical bond is one in which ________.

#Question id: 59

#Unit 1. Molecules and their Interaction Relevant to Biology

Nitrogen (N) normally forms three covalent bonds with a valence of five. However, ammonium has four covalent bonds, each to a different hydrogen (H) atom (H has a valence of one). What do you predict to be the charge on ammonium?

#Question id: 64

#Unit 1. Molecules and their Interaction Relevant to Biology

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? Testosterone and estradiol ________.

#Question id: 64

#Unit 1. Molecules and their Interaction Relevant to Biology

Testosterone and estradiol are male and female sex hormones, respectively, in many vertebrates. In what way(s) do these molecules differ from each other? Testosterone and estradiol ________.