A cell membrane is very specific about what it allows across. How does this help the cell?
A. Transport proteins allow only enzymes to pass through the
membrane.
B. The cell works better when it contains fewer proteins.
C. It helps the cell absorb as many different molecules as possible.
D. It is better for the cell if most molecules are prevented from
entering

What are tissues? a groups of tissues that work together b basic units of structure and function c groups of cells that perform the same function d multiple organs that perform a major function

How is ribosomal rna useful as a molecular clock? a. a large portion of the dna ring is not vital to structure or function, allowing it to accumulate neutral mutations. b. its rate of mutation increases over time as organisms continue to evolve and differentiate from each other. c. a slow mutation rate makes it useful for determining evolutionary relationships between ancient species. d. it is only found in select organisms, making it easier to compare relationships between species that have it.

All ova contain sex chromosomes corresponding to: x y xx xy