1 These can be two Excel files or an Excel File and a Microsoft Word file for example. 2  Press and hold down the Alt key on the keyboard. 3  Press and release the Tab key on the keyboard without letting go of the Alt key. 4  The ALT-TAB Fast Switching window should appear in the middle of your computer screen. Open at least two files in Windows. 2  These can be two Excel files or an Excel File and a Microsoft Word file for example. 3  Press and hold down the Alt key on the keyboard.
Merge this question into. Split and merge into it. Answer by Quirkyquantummechanic. Confidence votes 77.6K. Almost all of a mollusk shell is composed of calcium carbonate. It may take a few different forms and thereby appear differently, but CaCO3 is the main material in the shell.
The bivalves (meaning two-shells) are perhaps the most well known mollusks simply because of their history as a source of food. Clams, mussels, oysters and scallops are all bivalves. There are about 15,000 known species of bivalve, with about 80% of them being marine (the rest are found in fresh water).ollusks usually have a shell (although some do not). Mollusks also have an extension of the body wall called the mantle. This portion of the animal's anatomy is responsible for secreting the shell. The mantle encloses the mantle cavity which contains the Ctenidia (gills), anus and excretory pores.