Answer:
The answer is when the cell express different genes.
Explanation:
Cell differentiation is the process when a cell is changed from one cell type to an other and brings more complexity to the system. A cell before differentiation possess all the genes however their expression in turned off. When some external or internal factors trigger the gene expression it starts the cell differentiation. A multicellular organism undergoes several rounds of cell differentiation during its development. Although cell differentiation changes the size, shape and metabolic activity but the genetic makeup or DNA is never changed during cell differentiation.
Answer:
paleoclimatologists use different sources of information from fossils in order to record past climate and environmental conditions (for example, tree rings or skeletons of coral reefs)
Explanation:
Paleoclimatology is the discipline that studies ancient climate and environmental conditions. Paleoclimatologists are researchers that analyze different sources of evidence to obtain accurate records of past climate conditions. In this regard, the fossil record has proven to be a useful tool to obtain such information. For example, the rings of fossilized trees are usually wider during warm and wet years, while these rings become thinner during cold and dry years. Moreover, geochemical records from the skeletons of fossil corals (composed of calcium carbonate) are good indicators of past climate conditions because coral growth is sensitive to small fluctuations in water temperature. Paleoclimatologists also use non-biological climate indicators (e.g., sediments and ice sheets) to reconstruct past climate and environmental conditions.
2. The evolutionary process through which new species emerge
