Answer:
b. Only about one-half of the world's population relies on sunlight to maintain adequate vitamin D nutrition
Explanation:
Dark skin pigments slow down the synthesis of vitamin D, so black people need to spend more time in the sun to absorb enough vitamin D, so the letter A is incorrect.
Prolonged exposure to sunlight degrades the precursor of vitamin D, whereas prolonged exposure to sunlight produces vitamin D3, which acts to regulate heart function and blood pressure. With this we can conclude that the letter C is also incorrect.
Vitamin D deficiency is not caused by calcium deficiency, on the contrary, vitamin D deficiency is a cause of calcium deficiency. In addition, summer vitamin D synthesis stocks are usually not sufficient to meet summer vitamin D requirements. That is why the letter D is also incorrect.
We can conclude, then, that the correct answer is the letter B. The main source of vitamin production is through sun exposure, because type B ultraviolet rays (UVB) are able to activate the synthesis of this substance. Some foods, especially fatty fish, are sources of vitamin D, but the sun is responsible for 80 to 90% of the vitamin the body receives. It can also be produced in the laboratory and given as a supplement when there is a deficiency and for the prevention and treatment of a variety of diseases.
Which of the following is not a nucleotide found in DNA?uracil (U)If the sequence of one strand of DNA is AGTCTAGC, what is the sequence of the complementary strand?TCAGATCGIn addition to the base, what are the other components of a nucleotide?phosphate and sugarWhat does each chromosome contain?DNA and proteinsThe _______ chromosomes in a human cell from inside the cheek are found in the _______.46, nucleusYou can detect DNA that is specifically from the X chromosome in a DNA sample from a person. Why can't you definitively determine the gender of that person (male or female) from the presence of the X chromosome?Both males and females have an X chromosome so you would have to check for the presence of a Y chromosome.Human red blood cells are enucleated (that is, they do not have nuclei). Is it possible to isolate DNA from red blood cells? Why or why not?No, the genomic DNA is found only in nucleated cells.DNA replication is said to be semiconservative because a newly replicated, double-stranded DNA molecules consists of _______________.one old strand and one new strandWhich of the following statements about PCR is TRUE?DNA polymerase is the enzyme that copies DNA in PCR.What naturally occurring process does PCR mimic in a test tube?DNA replicationIf you start with one copy of a DNA fragment, how many rounds of PCR will it take to end up with a total of 32 copies?5<span>Complete the following statements regarding the steps necessary to copy a DNA sequence during PCR:
1) The two original strands of the DNA molecule can be separated by __________.
2) The enzyme ______________ "reads" each template strand and adds _______________ to make a new strand.</span>. 1) heat, 2) polymerase; complementary nucleotidesWhat is the purpose of careful primer design before PCR?Primers dictate the specificity of the place you are amplifying and Primers must "sit" on the original DNA strand to give polymerase a place to start replication.An individual's STR may vary from the same STR of another individual by _____________.The number of times a particular sequence is repeatedWhat represents genetic variation between individuals?the presence of STR's in their genomesGel electrophoresis separates DNA for profiling based on what?size (length)The entire sequence of DNA in a cell used for DNA profiling is called the ______genomeWhich STR will have migrated farthest through an electrophoresis gel?GAAG repeated twiceYou are studying the DNA profile of an individual, and you are looking at the results for a chromosome with just one STR site. How many bands will you see?either one or twoWhich of the following people would have DNA that is least similar to yours?your mother's brotherDNA evidence can give an investigator information regarding which of the following?family relationships between suspects, identity of an individual based on a profile, and locations of an individualHow many STRs are typically used to create a profile in forensic investigations?15You are investigating a crime. The DNA profile database has no perfect matches to the DNA collected at the crime scene. However, one profile in the database has at least one band in common with the crime scene DNA at every STR site. Which of the following is the most likely conclusion can you draw?A parent-child relationship exists between the DNA collected at the crime scene and the DNA in the database.From the STRs used in a forensic investigation, which STRs on which chromosomes would be particularly useful in determining whether crime scene evidence was left by a female or a male?Y chromosome STRFollowing mitosis and cytokinesis, daughter cells are _____genetically identical to each other and genetically identical to the parent cellIn the cell cycle, DNA is replicated during ____SWhich of the following processes require normal cell division?embryonic development, wound healing, replacement of blood cells, and intestinal tract and skin cell replacementDuring which stage of the cell cycle do sister chromatids separate from each other?anaphaseDuring which stage of the cell cycle are sister chromatids initially produced?interphaseDuring which stage of the cell cycle are sister chromatids first visualized?prophaseWhich of the following series has the stages of the cell cycle in the proper order?G1, S, G2, mitosis, cytokinesisIn which stage of the cell cycle does the cell spend the most time?interphaseWhich of the following series has the stages of mitosis in the proper order?prophase, metaphase, anaphase, telophaseWhat would be the result if a cell completed interphase and mitosis but failed to complete cytokinesis?You would only have one cell and You would have twice as many chromosomes as the parent cell.A normal cell that sustains irreparable DNA damage will most likely _____die by apoptosis
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I’m gonna go out on a limb and molecules
Answer:
question no 1 answer
A root hair,or absorbent hair, the rhizoid of a vascular plant, is a tubular outgrowth of a trichoblast, a hair-forming cell on the epidermis of a plant root. As they are lateral extensions of a single cell and only rarely branched, they are visible to the naked eye and light microscope. They are found only in the region of maturation of the root. Just prior to and during root hair cell development, there is elevated phosphorylase activity. Plants absorb water from the soil by osmosis. Root hair cells are adapted for this by having a large surface area to speed up osmosis. Another adaptation that they have is a large permanent vacuole.
question no 2 answer
Answer: Stems hold the plant upright and support it. They also transport water, minerals and sugars to the leaves and roots.
hope it helps
because i have taken it on by book
