Explanation:
The new research carried out by NASA on mars suggets that many of the Mars' ancient channel have been carved by flowing water, were actually formed by melt water beneath glacial ice sheets. The rocks looked familiar to the rocks found on Earth in these water channels. Moreover, conglomerate rock was found near the base of the channel on Mars.
Fish live completely in water, amphibians partly in water and land while reptiles live on land. Fish and reptiles have scales while amphibians have smooth skin. Fish breath through gills, amphibians through gills and lungs while reptiles through lungs. They are generally classified as vertebrates.
Ans.
Cell differentiation is defined as a process, by which less specialized cells, such as embryonic cells become more specialized. The process of cell differentiation is regulated by gene expression. Gene expression involves a specific group of genes that are turned on (expressed) or turn off (repressed) and dictates a cell's function.
A fertilized egg represents a single, non-specialized cell that develops into a complex, multicellular organism by cell differentiation. Thus, a adult rabbit looks so much different as compared to a single fertilized cell or zygote, due to cell differentiation, which is regulated by gene expression.
All cells are similar in composition and metabolic activities.
