Logic of a solution: *Carbon monoxide is a gas produced by furnaces and other devices that burn fuel. Cabins have wood burning stoves and propane furnaces. Carbon monoxide is a gas produced by burning propane.*
*(D)*
The original question: *What gas is produced by burning propane?
Options:
- (A) Greenhouse gases
- (B) Sulfur dioxide
- (C) gasoline
- (D) Carbon monoxide
- (E) hydrocarbons
- (F) carbon dioxide
- (G) dangerous
- (H) heating liquids*

Logic of a solution: *Soil can be depleted of nutrients. Dirt is really misplaced soil. Dirt can be depleted of nutrients.*
*(F)*
The original question: *When gardening what can be depleted of nutrients?
Options:
- (A) fertilizer
- (B) bacteria
- (C) the plant
- (D) coal
- (E) pine
- (F) the dirt
- (G) Acids
- (H) water*

Logic of a solution: *Behaviors that improve fitness increase through natural selection. Adaptation traits contribute to individual fitness and to the evolution of animal genetic resources. Behaviors can improve the evolution of animal genetic resources.*
*(F)*
The original question:
*The evolution of animal genetic resources can be impacted by:
Options:
- (A) extinction
- (B) Mars
- (C) competition
- (D) Darwin
- (E) agriculture
- (F) behavior
- (G) environment
- (H) Galapagos Islands*