I think the correct answer would be the third option. Organisms that help break down dead organic material so it can be recycled into a usable form for other organisms are called decomposers and this would include some of the bacteria. Also, there is a number of bacteria that are capable of breaking down some of the harmful products like in recent studies there are bacteria that could dechlorinate the toxic PCB substance. Some bacteria, as well, lives in the human intestines which aids in the breaking down of the food into useful molecules. The third option is partially true since there are some bacteria like the cyanobacteria which produces oxygen but it does not contribute largely to the oxygen present in the atmosphere.
Answer:
The correct answer is physical boundary.
Explanation:
In my opinion, the kind of boundary it signifies is the physical boundary. The physical boundary is the most general type and is a naturally taking place obstruction in between the two regions due to the existence of either an ocean, river, desert, or mountain ranges. At various occasions, the political boundaries between the states or the countries form along the physical boundaries.
The TYR, TRP2, and TRP1 genes are located next to each other on a single chromosome and are organized into an operon is most likely to be accurate.
The option a is correct.
Explanation:
The genes for the Tyrosinase, TRP2 and TRP1 are located on the same chromosome and are operons. These are operons because they are controlled by same transcription factors on mRNA.
Tyrosinase enzyme is important for the synthesis of melanin, eye pigments and hair colour. The synthesis of all these is completed in three distinct reactions catalysed by TRP1, TRP2 and Tyr genes. These work as operon and the protein product is almost 40% similar of the three genes.
The amount of melanin production depends on tyrosinase enzyme activity of all the three genes.
The genetic regulation is done by operons.
Answer:
1. Mutation- increase genetic variation
2. Selection- may increase, decrease or maintain genetic variation
3. Genetic drift- decrease genetic variation.
4. Gene flow- may increase or decrease genetic variation
Explanation:
1. A mutation refers to the changes in the DNA in an organism. The mutation of genes in DNA produces new adaptive features to evolve which increases the genetic variation of the organisms.
2. The natural selection favors the species which are best suited to live in that natural conditions. The natural selection, therefore, may increase or decrease the variation in a population.
3. Genetic drift is the phenomenon occurs due to random event which changes the gene pool of the population. When the genetic drift phenomenon is observed than the genetic variation of that population usually decreases.
4. Gene flow is the phenomenon in which the gene pool changes die to immigration and emigration. Therefore the phenomenon may increase or decrease genetic variation.
Answer:
The correct answer is option C. "arg+leu– or arg–leu+".
Explanation:
This bacteria is not able to growth on minimal medium or minimal medium supplemented with leucine. This means that the bacteria needs external supplementation of amino acids to growth, either arginine or leucine. Therefore, this bacteria can have the genotypes of arg+leu– or arg–leu+, meaning that the bacteria is able to synthesize either of two amino acids, but not both, because if that was the case the bacteria would be able to growth on minimal medium.
