Fossils are often hardened remains of organisms that once lived, such as a bone or tooth. Which characteristic of sedimentary rock makes it likely for fossils to be found in this type of rock?

A. An organism's remain become hardened when covered by melted rock.

B. Organisms are changed into rock by high temperature once they are no longer living.

C. The remains of organisms are buried under layers of sand, shells, and bits of rock.

D. The bones of an organism are pulled below Earth's surface during an earthquake.

Mouse liver cells were homogenized and the homogenate subjected to equilibrium density-gradient centrifugation with sucrose gradients. fractions obtained from these gradients were assayed for marker molecules (i. e., molecules that are limited to specific organelles). the results of these assays are shown in the figure. the marker molecules have the following functions: cytochrome oxidase is an enzyme involved in the process by which atp is formed in the complete aerobic degradation of glucose or fatty acids; ribosomal rna forms part of the protein-synthesizing ribosomes; catalase catalyzes decomposition of hydrogen peroxide; acid phosphatase hydrolysis monophosphoric esters at acid ph; cytidylyltransferase is involved in phospholipid biosynthesis; and amino acid permease aids in transport of amino acids across membranes. a) name the marker molecule and give the number of the fraction that is most enriched for each of the following cell components: lysosomes; peroxisomes; mitochondria; plasma membrane; rough endoplasmic reticulum; smooth endoplasmic reticulum.

When the oxygen produced by photosynthetic plants in the water dissolves in the water, which of these is being formed?

The cell membrane controls what enters and leaves the cell. which of the structures in the diagram below is the cell membrane? — f о