I believe animals that possess homologous structures probably evolved from the same ancestor. Homologous structures are similar because of common ancestry. A homologous structure is an example of an organ or bone that appears in different animals, underlining anatomical commonalities demonstrating descent from a common ancestor.
Plants inherit genes that enable them to produce chlorophyll, but this pigment is not produced unless the plants are exposed to light. this is an example of how the environment can influence on gene expression.
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Light has an important role in gene expression in plants by producing a number of light-induced changes. One of the examples of the light effects is that chlorophyll and the proteins required for assembling the photosynthetic apparatus are synthesized together with the enzymes needed for carbon fixation. Gene expression influenced by light includes the regulation at the level of transcription or, alternatively regulation of translation.</span>
Answer:
The crust is thinner and less dense than the mantle.
