Answer:
The correct answer is - 3/16 or 18.75% portion will be resistant to both Bt and DDT.
Explanation:
It is given that bollworms that are susceptible to Bt are represented by either RR or Rr and resistance one are shown by rr genotype and bollworms that are resistant to DDT are represent TT or Tt genotype and susceptible to DDT have tt genotype.
Cross: RR tt with rr TT
Gametes: Rt and rT
F1 cross:
RT
rT RrTt ( susceptible Bt and resistant DDT)
F1 Cross with F1
Gametes: RT, Rt, rT and rt
cross:
RT Rt rT rt
RT RRTT RRTt RrTT RrTt
Rt RRTt RRtt RrTt RrTt
rT RrTT RrTt rrTt rrTt
rt RrTt Rrtt rrTt rrtt
The bold genotypes are the three out of 16 that are resistant to both DDT and Bt.
Answer:
a, b, c are correct
Explanation:
Enhancers are DNA sequences that increase the rate of transcription. Enhancers act as binding sites for transcription factors that stimulate the transcription of one or more genes and enhancers stimulate transcription for specific cell type or tissue in a specific manner. The possible reasons for the lack of enhancers in bacteria include.
Enhancers often provide a mechanism for cell-specific transcription of genes, and most bacteria lack differentiated cell types.
Bacterial operons make coordinate regulation of protein synthesis by enhancers unnecessary.
There is little to no intergenic space on bacterial chromosomes, which makes long-range-acting enhancer sequences unnecessary.
Therefore, the correct options are (a), (b), and (c).
Answer:
the smell or taste of chicken salad
Explanation:
- A conditioned stimulus is the one which was previously a neutral stimulus but hen it gets paired with the unconditioned stimulus it leads to a conditioned response.
- The learned response which is produced in response to a neutral stimulus is the conditioned response.
- In the given condition the smell or taste of a chicken salad causes Allison to feel nauseated and hence, the taste or smell of a chicken salad is the conditioned stimulus which generates a conditioned response which in this case is nausea.
For evolution to occur:
There must be genetic variation in a population. This provides variation on which natural selection can act. Then natural selection can act by selecting those species which are better adapted to the environmental conditions. Over time those animals that are best suited to the environment only will survive and reproduce. Those organisms successful genes will be preserved and eventually the gene frequency in the population will change, changing the overall characteristics of a population. This is how evolution occurs.
The answer is; C
Homologous chromosomes have the same genes on the same loci. However, they may have different forms of the same gene called alleles. These sister chromosomes, of a homologous pair, separate during anaphase I of meiosis. The two daughter cells formed will, therefore, have half the genetic material as the parent cell. This is because they will only have one set of the genes (as in diploid organisms) and are called gametes.
