It’s true (a) because bones become brittle and easier to break if theyre not used. bones more frequently used become stronger.
Answer:
If I can deternine the field-of-view diameter, it makes it easy for me to determine the size of an organism in the field of view.
Explanation:
The advantages of knowing the diameter of the field of view at a given magnification are that I can have a mental picture of the approximate size of how large the specimens are when I can’t certainly determine them with a simple ruler and the metric system. It also enriches me with a good concept of vital ideas of the size of my samples and the size of what’s the organism.
The recombination frequency of the two gene pairs is 3%.
The number of recombinant offspring(r.o.) / total number of offspring x 100% = recombination frequency(θ):
r.o./total x 100% = θ
30/100 x 100% = 3%
Recombinant offspring are children that have a different allele combination to their parents.
For example, say a mother has a haploid cell with the alleles AB and the father has a haploid cell with the alleles ab. These combine to make a diploid cell with the sequence Aa+Bb.
Formation of Recombinant Offspring :
Recombination can happen in two different ways; independent assortment and crossing over.
- Independent assortment is when the maternal and parental DNA are mixed during meiosis, creating a new gene sequence.
- Crossing over happens during the first stage of meiosis when the two homologous chromosomes are paired and a portion breaks off on the same loci then reconnects to a different end. Crossing over can only happen when there isn't a physical linkage of the parental alleles.
Recombination frequency (θ) is the frequency with which a single chromosomal crossover will take place between two genes during meiosis. A centimorgan (cM) is a unit that describes a recombination frequency of 1%. In this way we can measure the genetic distance between two loci, based upon their recombination frequency. This is a good estimate of the real distance. Double crossovers would turn into no recombination. In this case we cannot tell if crossovers took place. If the loci we're analysing are very close (less than 7 cM) a double crossover is very unlikely. When distances become higher, the likelihood of a double crossover increases. As the likelihood of a double crossover increases we systematically underestimate the genetic distance between two loci.
When two genes are close together on the same chromosome, they do not assort independently and are said to be linked. Whereas genes located on different chromosomes assort independently and have a recombination frequency of 50%, linked genes have a recombination frequency that is less than 50%.
To learn more about Recombination frequency : brainly.com/question/7299933
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