Answer:
Industrial Revolution
Explanation:
In the 18th century, the industrial revolution took place. People started having more jobs than before and also getting paid for their labor. As the workers and employees were getting paid and jobs were available because of the industrial revolution, people started buying goods for their families. As a result, the standard of living also went up. Also, there was enough food for families to grow. As a result, the total population increased. In the 18th century, for the first time, the total population reached 1 billion landmarks.
Without a control group there wouldn’t be any basis for knowing if a result is due to the variable being tested
Answer:
Selection is a directional process that leads to an increase or a decrease in the frequency of genes or genotypes. Selection is the process that increases the frequencies of plant resistance alleles in natural ecosystems through coevolution, and it is the process that increases the frequencies of virulence alleles in agricultural ecosystems during boom and bust cycles.
Selection occurs in response to a specific environmental factor. It is a central topic of population and evolutionary biology. The consequence of natural selection on the genetic structure and evolution of organisms is complicated. Natural selection can decrease the genetic variation in populations of organisms by selecting for or against a specific gene or gene combination (leading to directional selection). It can increase the genetic variation in populations by selecting for or against several genes or gene combinations (leading to disruptive selection or balancing selection). Natural selection might lead to speciation through the accumulation of adaptive genetic differences among reproductively isolated populations. Selection can also prevent speciation by homogenizing the population genetic structure across all locations.
Selection in plant pathology is mainly considered in the framework of gene-for-gene coevolution. Plant pathologists often think in terms of Van der Plank and his concept of "stabilizing selection" that would operate against pathogen strains with unnecessary virulence. As we will see shortly, Van der Plank used the wrong term, as he was actually referring to directional selection against unneeded virulence alleles.
Answer:
Gravitational redshift
Explanation:
Gravitational redshift, changes in a planet's orbital path, gravitational lensing provides concrete evidence for the general theory of relativity. Hope this is helpful and the answer you were looking for!
