Biologist: Some small animals will instinctively go limp, “playing dead” when caught by a predator. But it is hard to see how playing dead can have survival value in this situation. The predator means to eat the animal just the same, whether or not it plays dead.

"Surprising" Phenomenon

Small animals sometimes play dead despite seemingly gaining no survival advantage from doing so.

Objective

The right answer will be a hypothesis that explains why small animals play dead. This explanation must make playing dead a rational thing for small animals to do when they’re caught by predators, likely by pointing out some survival advantage that the behavoir brings them.

A
Many small animal species will play dead when surprised by a loud noise or unexpected movement.

This seems as irrational as the behavior described in the stimulus. Why would playing dead protect small animals from the predators they imagine caused the loud noise or unexpected movement?

B
Predators often leave their food in a hiding place rather than eating it immediately.

If the small animals tried to escape, predators would know to kill them. But since predators think the small animals are dead, they simply bring them to a hiding spot to eat later. This allows the small animals to escape, which makes playing dead a clever, rational thing to do.

C
A small animal is more likely to play dead when caught by a predator if the predator species is common in the area.

We need to know how playing dead could possibly be useful for small animals. We don’t care about how common the predators are.

D
Most predators prey upon a variety of species, not all of which play dead when caught.

Sure, but why does it help small animals to play dead? We need to know how the behavior could be beneficial.

E
Many small animal species that do not play dead are capable of fighting off predators.

We know that the small animals in question were caught, so they’re definitely not fighting back. We need to know why they play dead rather than struggle to get free.


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If you use a wood stove to heat your home, you should use a wood-pellet stove rather than a regular wood stove. Because wood pellets are made from by-products of manufacturing processes that would otherwise go to landfills, heating a home with a wood-pellet stove will not cause more trees to be felled. The same cannot be said for regular wood stoves. So wood-pellet stoves are better for the environment than are regular wood stoves.

Summarize Argument
The main conclusion is that people who use a wood stove to heat their homes should use wood-pellet stoves instead of regular wood stoves. The author bases this on a subsidiary conclusion that wood-pellet stoves are better for the environment than regular wood stoves. The support for this subsidiary conclusion are the claims that wood-pellet stoves don’t cause more trees to be cut down, whereas regular wood stoves will cause more trees to be cut down.

Identify Conclusion
The conclusion is the author’s recommendation about what kind of wood stove to use: “If you use a wood stove to heat your home, you should use a wood-pellet stove rather than a regular wood stove.”

A
Wood pellets are made from waste products of manufacturing processes that would otherwise not be recycled.
This is a premise. The author uses this fact to establish that wood-pellet stoves are better for the environment than regular wood stoves, which in turn supports the author’s recommendation.
B
Heating a home with a wood-pellet stove is better for the environment than is heating a home with a regular wood stove.
This is a subsidiary conclusion. The author uses this to support the recommendation about what kind of wood stove to use.
C
Using a wood-pellet stove to heat one’s home does not cause trees to be felled.
This is part of the author’s support. Because wood-pellet stoves don’t cause more trees to be felled, whereas regular wood stoves do, wood-pellet stoves are better for the environment. This in turn supports the author’s recommendation.
D
Using a regular wood stove to heat one’s home causes trees to be felled.
This is part of the author’s support. Because wood-pellet stoves don’t cause more trees to be felled, whereas regular wood stoves do, wood-pellet stoves are better for the environment. This in turn supports the author’s recommendation.
E
People who use wood stoves to heat their homes should use wood-pellet stoves instead of regular wood stoves.
This is a paraphrase of the first sentence, which is the main conclusion.

4 comments