Starfish, sea urchins and sea cucumbers lack a what?
Options:
- (A) characteristics
- (B) the body's largest organ
- (C) watery habitat
- (D) centralized nervous system
- (E) functioning arm
- (F) underwater life
- (G) biological diversity
- (H) epidermis and dermis
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Let's think first: Echinoderms lack a centralized nervous system. Echinoderms include starfish, sea urchins, and sea cucumbers. Starfish, sea urchins and sea cucumbers lack a centralized nervous system.... So the answer is [(D)]

_ is how organisms grow and repair themselves.
Options:
- (A) complex
- (B) recycling
- (C) properties
- (D) fusion
- (E) fission
- (F) bacteria
- (G) Mitosis
- (H) potatoes
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Let's think first: Cell division is how organisms grow and repair themselves. Mitosis is cell division. Mitosis is how organisms grown and repair themselves.... So the answer is [(G)]

Where do organisms cluster on the ocean floor?
Options:
- (A) neutralized water
- (B) where they used to live
- (C) hot alkaline water
- (D) fissures of hot, acidic water
- (E) sedimentary rocks
- (F) fissures blasting cold water
- (G) at or near the margins
- (H) an area swollen with pus
--
Let's think first: Organisms cluster around hydrothermal vents in the ocean floor. Hydrothermal vents are fissures in the ocean floor that leak hot, acidic water. Organisms cluster around fissures in the ocean floor that leak hot, acidic water.... So the answer is [(D)]

What relaxes, thereby causing aneurysms?
Options:
- (A) layers of fat
- (B) Veins and arteries.
- (C) sweating
- (D) matter vibrating
- (E) blood vessels
- (F) the skin
- (G) Chemical energy
- (H) sensory neurons
--
Let's think first: Dilation occurs when cell walls relax. An aneurysm is a dilation of a blood vessel. Aneurysms are caused by relaxation of cell walls of blood vessels.... So the answer is [(E)]

Forests stabilize what influences what growth?
Options:
- (A) Trees
- (B) Energy
- (C) wind
- (D) seasons
- (E) rain
- (F) plant
- (G) Winter
- (H) Energy.
--
Let's think first: Climate influences plant growth, biodiversity, and adaptations of land organisms. Climate Forests stabilize climate. Forests stabilize what influences plant growth.... So the answer is [(F)]

What are critical for erectile health?
Options:
- (A) fur and fat
- (B) Energy.
- (C) Energy
- (D) sweating
- (E) exercise
- (F) arteries
- (G) strength
- (H) a cuticle
--
Let's think first: Arteries generally carry oxygen-rich blood. Oxygen-rich blood is critical for erectile health. Arteries are critical for erectile health.... So the answer is [(F)]