Explain the following: The texture of a pencil is smooth. A:chemical change B:chemical equation

C:physical property
D: physical change

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

one negative thing it that it can kill water animals. another negative thing is it can cause the destruction of ecosystem. one way water pollution can be reduced is to conserve energy.

the population of unionid mussels in the hudson river decreased after zebra mussels were introduced. zebra mussels, a nonnative species, competed with the unionid mussels for food. the zebra mussels were able to outcompete the unionid mussels, allowing the zebra mussel population to increase dramatically over six years. the unionid mussel population decreased due to a lack of food.

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