DDT was first used as an insecticide in 1942. Resistance genes existed before this time in houseflies and other insects. By 1970, no farmer would bother using this chemical. Why?
What will be an ideal response?
As DDT was used, the susceptible animals died, and only those with the natural ability to detoxify the poison were left to reproduce. Thus, the only insects left to reproduce were those with the successful trait. Farmers soon learned that the chemical was a waste of money.
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Cell walls are used by many different organisms for protection from their environment and structural support. These cell walls must obviously be insoluble in water; otherwise, they would dissolve the first time an organism got wet
Which of the following carbohydrates would you expect to be most soluble in water? A) starch B) peptidoglycan C) cellulose D) chitin
_____ in arteries sense changes in the acidity of the blood
a. Mechanoreceptors c. Photoreceptors b. Neurotransmitters d. Chemoreceptors
The serial endosymbiosis hypothesis states that the origin of mitochondria and chloroplasts was the result of a
mutually advantageous symbiotic relationship between two eukaryotic organisms. ______________c Indicate whether the statement is true or false.
Which of the following statements is false when comparing replication in eukaryotes and bacteria?
A. Both bacteria and eukaryotes use an ATP-dependent DNA ligase. B. In eukaryotes, replication is initiated by a number of proteins called the "origin recognition complex," whereas in bacteria, a single protein, DNaA, binds to the origin. C. Primers are made by the same RNA polymerase enzyme (primase) in both bacteria and eukaryotes. D. In bacteria the leading and lagging strands are made by the same polymerase, whereas in eukaryotes, the strands are made by different polymerases.