Genetic variation is essential for natural selection because natural selection can only increase or decrease frequency of alleles that already exist in the population. Genetic variation is caused by: mutation. random mating between organisms.
Answer:
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Answer:
b) plasmid
Explanation:
A plasmid is an extrachromosomal DNA molecule that found in a cell that replicates independently without the need for chromosomes. A plasmid is small and is also not attached to the chromosomal DNA. Generally, plasmids are a circular piece of double stranded DNA materials that are present in bacteria.
Plasmids are used in a molecular biology laboratory for gene manipulation. they are able to transfer genes to a DNA through DNA recombinant technology and also aid DNA replication in bacteria. Plasmids are also used to study antibiotic resistance.
During Pangea, Madagascar and India were one landmass. The species of frogs were homogenous across the
landmass. However, after continental
drift that began approximately 88 years ago,
allopatric speciation occurred to form different species on the two continents.
The dusky salamanders on the two continents that could once reproduce viable offspring 88 years
ago, cannot reproduce viably today because
they have diverged into two different species now.
