Line 1: *Lymphocytes are the key cells involved in the immune response. B lymphocytes produce antibodies . The key cells involved in the immune response produce antibodies.*
*(H)*
Line 2: *The cells that produce antibodies are key in what system?
Options:
- (A) health
- (B) T cells
- (C) vision
- (D) humans
- (E) macrophages
- (F) B cells
- (G) disease
- (H) immune*

Logic of a solution: *Aging is associated with the death of cells. Telomeres degrade as the cells divide and their shortening causes cell death. Aging is associated with degrading telomeres.*
*(D)*
The original question: *Aging is associated with degrading:
Options:
- (A) Most plants
- (B) an object
- (C) Acids
- (D) telomeres
- (E) layers of fat
- (F) Chlorophyll
- (G) vegetation
- (H) the skin*

Line 1: *Flatworms belong to the phylum Platyhelminthes. Most of the flatworms are parasitic, although the Turbellaria are free-living in fresh water. Phylum Platyhelminthes are mostly parasitic.*
*(E)*
Line 2: *Phylum platyhelminthes are mostly what?
Options:
- (A) animals
- (B) engorged
- (C) fungi
- (D) infected
- (E) parasitic
- (F) insects
- (G) huge
- (H) free living*

Logic of a solution: *Antigens are molecules that the immune system recognizes as foreign to the body. Bodies are physical entities. Antigens are molecules that the immune system recognizes as foreign to the physical entity.*
*(H)*
The original question: *What are molecules that the immune system recognizes as foreign to the physical entity?
Options:
- (A) bacteria
- (B) proteins
- (C) antibodies
- (D) Allergies
- (E) negative
- (F) immunities
- (G) parasites
- (H) antigens*

Line 1: *Ozone depletion results in higher levels of UV radiation reaching Earth. Ozone is represented chemically as O3. O3 depletion results in higher levels of UV radiation reaching Earth.*
*(A)*
Line 2: *The depletion of what results in higher levels of uv radiation reaching earth?
Options:
- (A) O3
- (B) O2
- (C) oil
- (D) pan
- (E) h2o
- (F) CO2
- (G) DNA
- (H) DDT*

Line 1: *Organisms that live in marine biomes must be adapted to the salt in the water. Another name for salt is sodium. Organisms that live in marine biomes must be adapted to the sodium in the water.*
*(C)*
Line 2:
*Organisms in a marine biome must be be adapted to what in the water?
Options:
- (A) mud
- (B) Nutrients
- (C) sodium
- (D) toxins
- (E) motion
- (F) sugar
- (G) energy
- (H) an anion*