A) The cells contain different genes and therefore express different genes.
Explanation:
In multicellular organisms, cells contain different genes and therefore express different genes.
If all the differentiated cells in an organism contain the same genes, and all the genes have the potential to be expressed, how do the cells become differentiated or specialized? The answer to this question is in the genes that are active in different cell types, that is, the great differences between cells in an organism result from the selective expression of genes. As a developing embryo undergoes successive divisions, specific genes are activated in different cells for different periods of time. Groups of cells follow distinct developmental pathways, and each group develops a particular type of tissue. Finally, in the mature organism, each cell type has a different pattern of genes that are expressed
Heat is then the by-product of the light energy from the Sun flowing through the biosphere. Organisms are inevitably dependent on sunlight to perform essential biological processes in order to sustain life. In the absence of this energy, all the organisms on Earth would die.
