Answer: Bacteria gain resistance to drugs because of mutations (permanent and random changes to their DNA) which means they have changed DNA coding, giving them the ability to resist the drug fighting them off. As a result, they survive and reproduce. Over time, more and more bacteria are generated as the DNA code for resistance is passed on over generations. This results in bacteria having the ability to resist drugs. This is particularly prevalent with antibiotics.
Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
then the moth would not have any spots
Answer:
Meiosis
Explanation:
Gene recombination refers to the mixture of genes from different individuals that occurs during sexual reproduction. Gene recombination is responsible for mixing between genes, which results in genetic variation in a bacterial population.
Genetic variability in a bacterial population occurs through three types of mechanisms: transformation, conjugation and transduction. However this genetic variation does not occur through Meiosis.
Transformation is the incorporation of free DNA by the bacterial cell. Conjugation is the process of transferring DNA from one bacterium to another, involving contact between the two cells. Transduction is the transfer of genetic material between cells, mediated by bacteriophages.
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