Which animal has a circulatory system with a three-chambered heart?
Options:
- (A) animals
- (B) Salamander
- (C) fur seals
- (D) mammals
- (E) alpacas
- (F) a fish
- (G) warm-blooded
- (H) barnacles
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Let's think first: Amphibians have a relatively complex circulatory system with a three-chambered heart. Frogs, toads and salamanders are amphibians. Salamanders have a relatively complex circulatory system with a three-chambered heart.... So the answer is [(B)]

_ is found in most molecules.
Options:
- (A) glucose
- (B) Gold
- (C) Energy
- (D) food
- (E) Polonium
- (F) Nitrogen
- (G) Helium
- (H) heat energy
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Let's think first: Nitrogen is found in proteins, nucleic acids, and chlorophyll. Most molecules are proteins or nucleic acids. Nitrogen is found in most molecules.... So the answer is [(F)]

Where do corals form large colonies?
Options:
- (A) Mars
- (B) new World
- (C) Sediment
- (D) shoreline
- (E) environment
- (F) Absorb light
- (G) loose soil
- (H) polyps
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Let's think first: Corals form large colonies in shallow tropical water. Water is shallow at the shore with gradual deepening. Corals form large colonies at the shoreline.... So the answer is [(D)]

What does the substance that male dogs have in urine to mark their territory do?
Options:
- (A) sweating
- (B) attract females
- (C) Release energy
- (D) repels females
- (E) attract enemies
- (F) attract males
- (G) adding heat
- (H) dangerous
--
Let's think first: Male dogs use pheromones in urine to mark their territory. Males produce 'pheromones' to attract females. Male dogs use something that attracts females in urine to mark their territory.... So the answer is [(B)]

Heavy metals are _.
Options:
- (A) emissions
- (B) dangerous
- (C) bent
- (D) homogenous
- (E) antigens
- (F) vehicles
- (G) fossil fuels
- (H) heat energy
--
Let's think first: Antigens are molecules that the immune system recognizes as foreign to the body. Heavy metals are, in general, foreign to the body. Heavy metals are antigens.... So the answer is [(E)]

How are plant cells around the vascular tissue created?
Options:
- (A) meiosis
- (B) metastasis
- (C) haleotosis
- (D) vegetation
- (E) shrub beds
- (F) made
- (G) homogenous
- (H) mitosis
--
Let's think first: Secondary meristem is located within and around the vascular tissues. Plant cell types rise by mitosis from a meristem . Plant cells around the vascular tissues are created by mitosis.... So the answer is [(H)]