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: *Energy is passed up a food chain or web from lower to higher trophic levels. Energy and carbon in organic compounds passed through food chain to herbivores and carnivores. Carbon in organic compounds are passed through the food web from herbivores to carnivores.*
*(E)*
Line 2: *Carbon in organic compounds are passed through the food web from what?
Options:
- (A) it helps plants in growing
- (B) Burning fuel and air
- (C) members of their own species
- (D) people to dogs
- (E) herbivores to carnivores
- (F) carnivores to plants
- (G) passenger pigeons
- (H) predators to prey*

Logic of a solution: *Blood pressure is highest in arteries and lowest in veins. Veins are vessels that bring blood to the heart. Vessels that bring blood to the heart have lower blood pressure than arteries.*
*(B)*
The original question: *Vessels that bring blood to the hard have lower blood pressure than
Options:
- (A) the skin
- (B) arteries
- (C) archery
- (D) heat or cold
- (E) exercise
- (F) artefact
- (G) artesan
- (H) lungs*

Line 1: *Arteries generally carry oxygen-rich blood. Arteries carry blood away from the heart. Something that brings blood away from the heart carries oxygen-rich blood.*
*(H)*
Line 2: *What direction does something that has oxygen-rich blood go?
Options:
- (A) mouth of rivers
- (B) the body's largest organ
- (C) move to different locations
- (D) Earth orbiting the Sun
- (E) Move to another area
- (F) to move people
- (G) animal transport
- (H) Away from the heart*

Logic of a solution: *Menopause occurs when menstruation stops occurring, usually in middle adulthood. Middle adulthood begins around age 35 to 40 and continues through age 65 to 70. Menopause occurs when menstruation stops occurring, usually between 35 and 65 years old.*
*(F)*
The original question: *In what timeframe does menopause typically occur?
Options:
- (A) Earth orbiting the Sun
- (B) an organism's body
- (C) Veins and arteries.
- (D) the rest of the body
- (E) By wind and rain
- (F) 35-65 years old
- (G) major threat to health
- (H) Decrease bodily water*

Logic of a solution: *Most protists have motility. Protists Protists are single-celled organisms. Most single-celled organisms are motile.*
*(D)*
The original question:
*What is one thing most single-celled organisms have in common?
Options:
- (A) Energy
- (B) glucose
- (C) bacteria
- (D) motility
- (E) Energy.
- (F) heat energy
- (G) resistance
- (H) warmth*