Which of the following forms a protective layer outside of the plasma membrane of the plant cell?
A. cell wall
B. cellulose
C. chitin
D. pectin
E. proteoglycans
A. cell wall
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Bacteria ____
a. are diploid organisms b. produce gametes c. have a life cycle that varies between unicellular stage and multi-cellular stage d. have a single circular chromosome e. lack both DNA and RNA
Is most of our DNA made up of genes?
A) Yes, the vast majority of human DNA consists of genes. B) No, genes make up only 1.5% of our DNA.
When molecules move through a cell membrane from an area of greater concentration to an area of lesser concentration by way of a channel protein, it is called:
A. endocytosis B. exocytosis C. facilitated diffusion D. osmosis E. simple diffusion
Select the option that best finishes the following statement: "Evolution is a process __________."
(a) that can be understood based on the principles of mutation and selection. (b) that results from repeated cycles of adaptation over billions of years. (c) by which all present-day cells arose from 4–5 different ancestral cells. (d) that requires hundreds of thousands of years.