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Leaves fall to the warm, and damp forest floor, they decay and release nutrients.

Leaves fall to the warm, damp forest floor, and they decay and release nutrients.

Leaves fall to the warm and damp forest floor, they decay and release nutrients.

Leaves fall to the warm, damp forest floor and they decay and release nutrients.

In rain forests, trees form a dense canopy for most of the sunlight is shut out.

In rain forests, trees form a dense canopy, so most of the sunlight is shut out.

In rain forests, trees form a dense canopy, for most of the sunlight is shut out.

In rain forests, trees form a dense canopy so most of the sunlight is shut out.

Animals need forests in order to live, or forests provide places to live and sources of nourishment.

Animals need forests in order to live, but forests provide places to live and sources of nourishment.

Animals need forests in order to live, for forests provide places to live and sources of nourishment.

Animals need forests in order to live, so forests provide places to live and sources of nourishment.

There is a carefully balanced food chain in forests, for this nourishes all forest creatures.

There is a carefully balanced food chain in forests, or this nourishes all forest creatures.

There is a carefully balanced food chain in forests, yet this nourishes all forest creatures.

There is a carefully balanced food chain in forests, so this nourishes all forest creatures.

Some countries cut down rain forests but they institute programs to help maintain the forest as a resource.

Some countries cut down rain forests, for they institute programs to help maintain the forest as a resource.

Some countries cut down rain forests, but they institute programs to help maintain the forest as a resource.

Some countries cut down rain forests for they institute programs to help maintain the forest as a resource.

Acid rain, a product of air pollution mixing with rain to develop sulfuric acid, and is a threat, it has damaged some forests.

Acid rain, and a product of air pollution mixing with rain to develop sulfuric acid, is a threat, it has damaged some forests.

Acid rain, a product of air pollution, and rain to develop sulfuric acid, is a threat, it has damaged some forests.

Acid rain, a product of air pollution mixing with rain to develop sulfuric acid, is a threat, and it has damaged some forests.

Forests perform several vital functions for other living things, for they clean carbon dioxide from the air and prevent soil erosion.

Forests perform several vital functions for other living things they clean carbon dioxide from the air, and prevent soil erosion.

Forests perform several vital functions, for other living things they clean carbon dioxide from the air and prevent soil erosion.

Forests perform several vital functions for other living things, they clean carbon dioxide from the air and prevent soil erosion.

People have been clearing forests for thousands of years, so deforestation has increased as the earth's population has increased.

People have been clearing forests for thousands of years, for deforestation has increased as the earth's population has increased.

People have been clearing forests for thousands of years, yet deforestation has increased as the earth's population has increased.

People have been clearing forests for thousands of years, or deforestation has increased as the earth's population has increased.

In order to help save forests, governments have set aside national parks, so groups replace felled trees with new ones.

In order to help save forests, governments have set aside national parks, for groups replace felled trees with new ones.

In order to help save forests, governments have set aside national parks, but groups replace felled trees with new ones.

In order to help save forests, governments have set aside national parks, and groups replace felled trees with new ones.