Question

read the passage. there are several questions about this passage.
the author is a biologist and college professor. he is considered one of the world’s experts on snakes.

from tracks and shadows

1
rainforests are dimly lit and exceptionally diverse—claustrophobically dark and fecund¹—so no wonder tropical biologists end up puzzling over existential questions. at la selva biological station in costa rica, giant trees with buttressed trunks tower overhead, obscuring the sky, and every glimpse holds the vibrant greens and somber browns of plants and their decaying remnants. after a torrential shower the air reverberates with the buzzes, whines, and clicks of insects. mantled howler monkeys sound off in the distance. all around us leaf litter reeks from the chemical adventures of microbes, and over the course of hours my puny primate nose wrinkles toward some collared peccaries,² then heaps of rotting fruit and a pile of cat droppings. rounding a trail curve i’m baffled by a shimmering lavender stripe, dozens of yards long and a half-inch tall; then i drop to my knees and contemplate thousands of leaf-cutter ants, each carrying a single delicate flower petal. and from time to time, slogging along the muddy paths, i imagine being overgrown by mosses and fungi, or devoured by spike-headed katydids³ the size of small mice.

2
setting aside matters of life and death for the moment, what do ecologists mean by “exceptionally diverse,” and why might anyone care? a comparison among some familiar places illustrates how numbers of species increase toward the equator, culminating in unparalleled tropical richness. california reaches from death valley’s floor to mount whitney’s summit, spans parched salt flats to drenched redwood groves, and yet across ten degrees of latitude boasts only thirty-five species of snakes. almost twice that number occur in la selva’s five square miles, as if a house full of serpents were marked into a thimble and there are nearly
this question has two parts. answer part a, and then answer part b.

part a
select two statements that best express central ideas in the passage.
☐ 1. several animal species in the rainforests are the most endangered in the world.
☐ 2. travelers to costa rica seldom get to see many of the animal species in rainforests.
☐ 3. rainforests support a greater number of plant and animal species than other regions do.
☐ 4. the geological location and local conditions of rainforests create variety in plant and animal species.
☐ 5. la selva biological station is an exceptional location for studying plant and animal species in rainforests.

part b
how does the author mainly develop the correct central ideas from part a?

Explanation:

Part A

To solve this, we analyze each option:

• Option 1: The passage doesn't focus on endangered species, so eliminate.
• Option 2: The passage is about rainforest diversity, not travelers' experiences, eliminate.
• Option 3: The passage mentions "exceptionally diverse" and compares species numbers (e.g., California vs La Selva), so this is a central idea.
• Option 4: The rainforest's environment (dimly lit, fecund, etc.) and location (tropical, near Equator) are linked to species variety, so this is a central idea.
• Option 5: While La Selva is used as an example, the main idea isn't about it being exceptional for study, but about rainforest diversity, eliminate.

So the correct options for Part A are:

1. Rainforests support a greater number of plant and animal species than other regions do.
2. The geological location and local conditions of rainforests create variety in plant and animal species.

Part B

The author mainly develops the central ideas (rainforest diversity and its causes) by:

• Providing descriptive details of the rainforest environment (e.g., dimly lit, fecund, plant/animal descriptions) to show the conditions that allow for diversity.
• Using a comparison (between California's species count and La Selva's) to illustrate that rainforests (near the Equator) have more species, supporting the idea that location/conditions drive diversity and that rainforests have more species than other regions.

For Part B, a common way the author develops the ideas is by using vivid descriptions of the rainforest's environment (to show what creates diversity) and a comparison of species numbers between different regions (to show rainforests have more species). For example, describing the rainforest's dark, fecund environment (supporting the idea that conditions create variety) and comparing snake species in California and La Selva (supporting the idea that rainforests have more species).

Final Answers

Part A

1. Rainforests support a greater number of plant and animal species than other regions do.
2. The geological location and local conditions of rainforests create variety in plant and animal species.

Part B

The author mainly develops the central ideas by describing the rainforest’s environment (to show how local conditions create species variety) and comparing species numbers between different regions (e.g., California and La Selva) to show rainforests have more species. (Or, more specifically, using descriptive details of the rainforest ecosystem and a comparative example of species counts to illustrate the central ideas about rainforest diversity and its causes.)

Answer:

Part A

To solve this, we analyze each option:

• Option 1: The passage doesn't focus on endangered species, so eliminate.
• Option 2: The passage is about rainforest diversity, not travelers' experiences, eliminate.
• Option 3: The passage mentions "exceptionally diverse" and compares species numbers (e.g., California vs La Selva), so this is a central idea.
• Option 4: The rainforest's environment (dimly lit, fecund, etc.) and location (tropical, near Equator) are linked to species variety, so this is a central idea.
• Option 5: While La Selva is used as an example, the main idea isn't about it being exceptional for study, but about rainforest diversity, eliminate.

So the correct options for Part A are:

1. Rainforests support a greater number of plant and animal species than other regions do.
2. The geological location and local conditions of rainforests create variety in plant and animal species.

Part B

The author mainly develops the central ideas (rainforest diversity and its causes) by:

• Providing descriptive details of the rainforest environment (e.g., dimly lit, fecund, plant/animal descriptions) to show the conditions that allow for diversity.
• Using a comparison (between California's species count and La Selva's) to illustrate that rainforests (near the Equator) have more species, supporting the idea that location/conditions drive diversity and that rainforests have more species than other regions.

For Part B, a common way the author develops the ideas is by using vivid descriptions of the rainforest's environment (to show what creates diversity) and a comparison of species numbers between different regions (to show rainforests have more species). For example, describing the rainforest's dark, fecund environment (supporting the idea that conditions create variety) and comparing snake species in California and La Selva (supporting the idea that rainforests have more species).

Final Answers

Part A

1. Rainforests support a greater number of plant and animal species than other regions do.
2. The geological location and local conditions of rainforests create variety in plant and animal species.

Part B

The author mainly develops the central ideas by describing the rainforest’s environment (to show how local conditions create species variety) and comparing species numbers between different regions (e.g., California and La Selva) to show rainforests have more species. (Or, more specifically, using descriptive details of the rainforest ecosystem and a comparative example of species counts to illustrate the central ideas about rainforest diversity and its causes.)