Answer:
When directed mutagenesis which is also called reverse genetics is used, only a single mutation per genome is introduced. In contrast, the number of mutations per genome introduced by random mutagenesis is usually difficult to control. It is likely that the strain you obtained with a mutation in gene X after random mutagenesis contained an additional mutation or perhaps multiple mutations which ultimately was/were responsible for loss of virulence in your favorite pathogen.
Answer:
1. Survivors of the pesticide have a gene that protects them from it.
2. Then the survivors pass on the gene to their offspring,
3. Each time the pesticide is sprayed, the insects have a greater chance of survival.
Same genus is more closely related. The farther down the list Phylum-Class-Order-Family-Genus-Species you go, the more closely related are the species in that taxon.
To have similar shape or function, although not derived from similar lineage.
The correct answer is b: cattle on rangeland. A point source of pollution occurs from a single identifiable and usually spatially narrow source. These sources of pollution are usually relatively easily to quantify and manage. In contrast, a non-point source of pollution, such as cattle on rangeland or irrigated agriculture, is variable on both spatial and temporal scales. These sources of pollution are difficult to quantify and manage.
