Problem:OPTIONS:
- pollination
- sound
- Vibrates
- impregnation
- Decibels
- fertilization
- courtship
- pollen

You are presented with the quiz "Copulation is generally preceded by what?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "mating is generally preceded by courtship" and "copulation starts early in the mating season and usually stops when nesting begins". So, what's the best answer to the question?
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A: courtship

Problem:OPTIONS:
- rust
- vomit
- reacts
- bruise
- divide
- expand
- harm
- burned

You are presented with the quiz "What does chemical weathering cause iron to do?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "chemical weathering causes iron in rock to oxidize" and "when iron oxidizes, it rusts". So, what's the best answer to the question?
****
A: rust

Problem:OPTIONS:
- carbon dioxide
- Hydrogen and oxygen
- organic molecules
- deoxyribonucleic acid
- carbohydrates
- Converted sugar
- genetic material
- solid, liquid, gas

You are presented with the quiz "For survival, plants require a compound made of what?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "aplants require water for survival" and "water is a compound of hydrogen and oxygen". So, what's the best answer to the question?
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A: Hydrogen and oxygen

Problem:OPTIONS:
- during the night
- they bend
- during prophase
- during reproduction
- an organism's body
- solid, liquid, gas
- during protein absorbtion
- Veins and arteries.

You are presented with the quiz "Structures coil when, and are made of DNA and proteins?" But you don't know the answer, so you turn to your teacher to ask for hints. He says that "chromosomes are coiled structures made of DNA and proteins" and "during prophase the chromosomes coil up". So, what's the best answer to the question?
****
A:
during prophase