Logic of a solution: *All chemical reactions require activation energy to get started. Activation energy is required to overcome the energy barrier. All chemical reactions must first overcome the energy barrier.*
*(D)*
The original question: *What must a chemical reaction overcome before starting?
Options:
- (A) PV=nRT
- (B) heat or cold
- (C) reactants
- (D) energy barrier
- (E) Dehydration
- (F) harmful substances
- (G) resistance
- (H) temperature*

Line 1: *Carbon may be stored in sedimentary rock for millions of years. Sedimentary Rocks One of the commonest sedimentary rocks is sandstone. Carbon may be stored in sandstone for millions of years.*
*(C)*
Line 2: *What element may be stored in sandstone for millions of years?
Options:
- (A) copper
- (B) calcium
- (C) carbon
- (D) chemicals
- (E) heat
- (F) iron
- (G) rock
- (H) fossils*

Logic of a solution: *Chromosomes are the form of the genetic material of a cell during cell division. Microtubules form part of the mitotic spindle that moves the chromosomes during cell division. Microtubules move the genetic material of a cell during cell division.*
*(B)*
The original question: *What structure moves the genetic material of a cell during cell division?
Options:
- (A) an organism's body
- (B) microtubules
- (C) Most plants
- (D) Chemical energy
- (E) Plant reproduction
- (F) Electrical energy
- (G) pollen
- (H) A computer*

Line 1: *Macroevolution occurs over geologic time above the level of the species. And geologic time is very, very slow. Macroevolution occurs very, very slowly above the level of the species.*
*(B)*
Line 2: *Macroevolution occurs how above the level of the species.
Options:
- (A) swiftly
- (B) slowly
- (C) quickly
- (D) forces
- (E) never
- (F) ferns
- (G) animals
- (H) three*

Logic of a solution: *Viruses cause many human diseases. Examples include influenza, rabies, HIV, and Herpes viruses. Influenza causes human disease.*
*(F)*
The original question: *What causes human disease?
Options:
- (A) HPV
- (B) UV
- (C) minerals
- (D) Tamiflu
- (E) mold
- (F) HIV
- (G) human growth
- (H) CFCs*

Logic of a solution: *Some viruses live in a dormant state inside the body. When ferns are dormant it is as if they are hibernating. Some viruses live in a hibernating state inside the body.*
*(E)*
The original question:
*What can stay hidden in a hibernating state inside the body?
Options:
- (A) infections
- (B) blood cells
- (C) fungi
- (D) insects
- (E) viruses
- (F) honeybees
- (G) plasma
- (H) barnacles*