Answer is A. A population becomes separated by environmental factors into two groups that do not reproduce with one another.
When a population of a species become geographically separated then gene flow between them stops. Over a period of time, the population may become genetically different in response to the natural selection due to different environments. Selection and genetic drift will act differently on these two separated populations. This will results into two separate species. This type of speciation is called allopatric speciation.
Answer:
Adaptive radiation
Explanation:
Adaptive radiation occurs when an ancestral species move to a new environment that has various resources that are necessary for survival and also has environmental conditions that would ensure its offspring adapt well over time. In this new environment, the ancestral species would produce offspring with different traits and behaviors that will allow them to survive in this new environment while occupying their various niches. Over a relatively short time, different species arising from the common ancestor would occupy the new environment.
Answer:
Background
During the course of a bacterial infection, the rapid identification of the causative agent(s) is necessary for the determination of effective treatment options. We have developed a method based on a modified broad-range PCR and an oligonucleotide microarray for the simultaneous detection and identification of 12 bacterial pathogens at the species level. The broad-range PCR primer mixture was designed using conserved regions of the bacterial topoisomerase genes gyrB and parE. The primer design allowed the use of a novel DNA amplification method, which produced labeled, single-stranded DNA suitable for microarray hybridization. The probes on the microarray were designed from the alignments of species- or genus-specific variable regions of the gyrB and parE genes flanked by the primers. We included mecA-specific primers and probes in the same assay to indicate the presence of methicillin resistance in the bacterial species. The feasibility of this assay in routine diagnostic testing was evaluated using 146 blood culture positive and 40 blood culture negative samples.
Explanation:
Results
Comparison of our results with those of a conventional culture-based method revealed a sensitivity of 96% (initial sensitivity of 82%) and specificity of 98%. Furthermore, only one cross-reaction was observed upon investigating 102 culture isolates from 70 untargeted bacteria. The total assay time was only three hours, including the time required for the DNA extraction, PCR and microarray steps in sequence.
Adult frogs are on land and they have feet and a body
Tadpoles are in water and they are somewhat like a fish!
Answer:
D.
Both the femur and humerus bone have what's called 'spongy bone' inside them and hollow spaces full of yellow and red bone marrow. Additionally, both bones do not attach to the axial skeleton but rather attach to the pelvic or hip bones; while they are both strong bones, they are not made of only compact bone but are made of 'spongy bone' inside them. Lastly, they do not protect any organs but rather allow for movement. D, They both have hollow spaces filled with bone-generating cells, is the best answer in this case
Explanation:
