Answer:
PCBs and DDT are chemicals that were banned more than 30 years ago, but our air, water, land, and bodies are so contaminated that decades of cleanup efforts have yet to eliminate their threats to our health. Today, food is one of the most likely exposure routes to PCBs.
I believe the answer is A. True.
Answer:
this is chemistry not biology
Answer:
See
Explanation:
Given:
Brown allele (B) is dominant over the white allele (b).
It will be assumed that the alleles are not related to the X and Y chromosomes.
See attached diagram for details of the general case (for both homo-zygous and hetero-zygous parents)
For both parents hetero-zygous,
P1:
Genotype: Bb (100%)
Phenotype: brown (100%)
F1:
Genotypes : BB, Bb, bB and bb in equal proportions, i.e.
BB (25%), Bb (50%), bb (25%)
Phenotypes: 75% brown (from BB and Bb), 25% white (from bb)
Answer:
d.They prevent the two parental strands from coming together again.
Explanation:
During the process of DNA replication, the two DNA strands should be separated from each other to serve as a template. To separate the two DNA strands, the helicase enzyme breaks down the hydrogen bonds between the complementary base pairs of the DNA strands. The process uses ATP as a source of energy.
Due to the presence of complementary base pairs, the separated DNA strands have a tendency to reanneal by the formation of hydrogen bonds. To prevent the reannealing of separated DNA strands, single stranded binding proteins bind to them. Binding to single stranded binding proteins to the separated DNA strands does not allow them to reanneal.