13) according to theories concerning the origin of life, the atom shown is a likely choice for the basic element of all livings things because it a) is small and unstable. b) is relatively stable and can form four covalent bonds. c) forms four ionic bonds with other elements and itself. d) is large and takes up enough space to fill the structure of a cell.

Complete the possible outcomes for each generation in the pedigree chartaa aa aa

The pharynx is the structure in the body that serves as a pathway of both air and food. how does the body make sure that food does not get into the lungs? the salivary glands secrete enzymes that pull food out of the air pathway. the small intestine pushes the air out of the digestive system. the pancreas breaks down food in the air pathway. the epiglottis closes the air pathway so that food will not enter it.

Which set of characteristics best describes sedimentary rock? a) largest type of rock, made of organic matter, hardest type of rock b) often contains layers, forms near sources of water, contains fossils c) least abundant type of rock, made of other rocks, made mostly of minerals d) most abundant type in earth's crust, made of magma/lava, contains no fossils