1.a scientist wants to prevent a culture of live cells from producing a particular protein. which of the following will the scientist most likely modify to prevent the production of the protein? * a. the dna in the nucleus b. an enzyme in the lysosomes c. the polysaccharides in the cytoplasm d. a phosopholipid in the cell membrane 2.which of the following statements explains why the insertion of a nucleotide into a dna sequence can result in a phenotypic change in the offspring? * a. the dna would no longer fit through the nuclear membrane to get to ribosomes for translation b. the sequence of nitrogenous bases in the dna would no longer code for the correct amino acids c. fatty acids would no longer attach to the dna strands to transcribe the dna d. antibodies would no longer recognize the dna as belonging to the cell and would destroy the dna 3.if the producers in a food web were removed, which of the following changes would most likely occur? * a. the entire food web would collapse over time. b. the food web would depend on the decomposers for energy c. the consumers would begin making energy for the food web d. the populations of the remaining organisms in the food web would increase 4.prolonged periods of drought in an area cause decreases in plant population sizes. which of the following statements describes how the decreases in plant population sizes then affect other populations in the area? * a. omnivore population sizes increase, and herbivore population sizes increase b. omnivore population sizes decrease, and carnivore population sizes increase c. herbivore population sizes increase, and carnivore population sizes decrease d. herbivore population sizes decrease, and carnivore population sizes decrease 5.the oceans have become increasingly acidic in recent years as the water absorbs more and more carbon dioxide from the atmosphere. this increased acidity interferes with the ability of corals to maintain their skeletons. in addition, an increase in water temperatures worldwide is causing coral bleaching, another condition that threatens the health of coral reefs. based on this information, which of the following would most improve the health of coral reefs? * a. reducing the use of fossil fuels b. eliminating nuclear power plants c. removing more natural gas embedded in rocks d. replacing offshore oil drills with onshore oil drills

1.   A

Explanation: For a cell to form proteins, the specific types of proteins are coded for by the genes in DNA (found in the chromosomes of the nucleus). To produce proteins, the genes are first transcribed by RNA polymerase to form messenger-RNA. The mRNA is then translated into proteins by ribosomes in the cytoplasm of the cell.

2. B

Explanation: Translation of genes into proteins is dependent on the sequence of nucleotides. They are translated in sequences of 3 nucleotides known  as codons. Therefore adding a nucleotide on a piece of DNA causes what is referred to as a frame-shift mutation. The 3 sequences (of codons) is interrupted and shifted by one nucleotide. Therefore, the codons change and the amino acids translated will also change.

3. A

Expanation: Producers are significant in a food chain because they incorporate the energy of the sun into the food chain. This is why they are at the base of the food chain and have the largest biomass. They are consumed by primary consumers which are consumed by secondary consumers which are consumed by tertiary consumers and so on.  

4. D

Explanation: Plants are consumed by herbivores. Therefore, a decrease in plant population due to drought was resulted to decrease in herbivore population. This is due to stiff competition by the herbivores for the scarce plant population. Carnivores consume herbivores. Due to a decrease in the herbivore population, then the carnivore population would also decrease.

5. A

Explanation: Burning of fossil fuels emits carbon dioxide gas which is a greenhouse gas. Greenhouse gas traps infrared wavelength of lights hence warming up the atmosphere, causing global warming. Reduction  in use of fossil fuels will hence alleviate an increase in global temperature hence protect coral in the oceans from bleaching.  

answer-

the statement that f(x) = |x+a| + b has exactly one x-intercept is sometimes correct.

solution-

it solely depends on b, whether the function will have one or two or zero x intercept.

this plot of the given function, f(x) = |x+a| + b will be the basic absolute value graph i.e v shape, with vertex translated to (-a, b), instead of origin.

1-   if b is zero, the graph will have exactly one x-intercept, at x= -a

2- if b is positive, the whole graph will be above the x-axis, hence it will have no x-intercepts.

3- if b is negative, the graph will be below the x-axis, hence it will have two x-intercepts.

∴ the statement is sometimes true.