Clay minerals and quartz these two are most common detrital sedimentary rocks
a combined transmitter and receiver called a transducer sends a sound pulse straight down into the water and the pulse moves through the water and bouces off the ocean bottom so that the transducer is able to pickup the reflected sound
Every cell of the organism has the same DNA sequence and same genes. However, not all genes are expressed in every single cell at the same time. Only those genes necessary for a specialised function of a specialised cell are expressed in the specialised cell. For example, skin cells have some different proteins than nerve cells. Genes responsible for those "skin proteins" are activated in skin cells and are turned off in nerve cells.
