is an alteration in the base-pair sequence of an individual's DNA; may arise spontaneously or following exposure to a mutagen.

Mutation

Mutation is an alteration in the base-pair sequence of an individual's DNA; may arise spontaneously or following exposure to a mutagen.

Explanation:

A mutation could occur when a chemical agent known as mutagen changes the genetic material, usually DNA, of an organism and this increases the frequency of mutations above the natural background level.

Other causes of mutation include:

- spontaneous mutation

- error in DNA replication, repair and recombination

- induced mutations by mutagens exposure

Examples of mutagens are X-ray, heavy metals such as cadmium, lead etc

the solute can move "downhill," from regions of higher to lower concentration, relying on the specificity of the protein carrier to pass through the membrane. this process is called passive transport or facilitated diffusion, and does not require energy.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

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