Thoreau writes, "when our lives cease to be inward and private, conversation degenerates" to become
a. mere gossip.
b. a fantasy about a fiction.
c. mindless and sterile.
d. seeking an advantage over others.

"the idea of humanism is mostly adeptly reflected in renaissance art by a focus on the body itself, especially with sculpture, where many detailed portraits of the human body (such as the david) were created."

option c (nickel) is not found in earth's crust. the earth's crust basically contains eight (8) elements namely: oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium (listed in order of abundance).