Answer:
The answer is (d) Three genes, each with two alleles that act additively.
Explanation:
1/ The genotype of P is AABBCC and aabbcc, for example. Then, F1 should be AaBbCc.
The genotype of individuals with n heterozygous pair is 2^n. Thus, in this case, the number of genotype in F2 should be 2^3 * 2^3 = 8 * 8 = 64. We can get this conclusion by analyzing the number of 6 cm tails in F2: 1/64 with genotype aabbcc, and the number of 30 cm tails: 1/64 with genotype AABBCC. These two genotypes is as same as the ancestor in this experiment.
The genotype of an F2 piglet with an 18 cm tail is AaBbCc. If these genes show dominance, the tail lenght of F2 will be 30 cm. And there are 7 possible phenotypes. Thus, we can conclude that the genes act additively.
2/ 18 cm tail F2: AaBbCc, and 6 cm tail: aabbcc.
The offspring genotypes are:
The frequency of piglets with 14 cm tail length should be 3/8 = 37.5%.
Answer and Explanation:
1) These results are consistent with option (d)Three genes, each with two alleles that act additively .
Quantitative heritability: Refers to the transmission of a phenotypic trait in which expression depends on the additive effect of a series of genes.
Polygenic heritability occurs when a trait is due to the action of more than one gene that can also have more than two alleles. This can cause many different combinations that are the reason for genotypic graduation.
Quantitative traits are those that can be measure, such as longitude, weight, eggs laid per female, among others. These characters do not group individuals by precise and clear categories. Instead, they group individuals in many different categories that depend on how the genes were intercrossed and distributed during meiosis. The result depends on how each allele of each gene contributed to the final phenotype and genotype.
In the exposed example, there are 7 different phenotypes (6, 10, 14, 18, 22, 26, 30) and the majority of F2 individuals have 18-lengthed tails. This might be the heterozygotic phenotype for all the genes.The rest of the phenotypes are possible combinations of genes and their alleles. There are six possible combinations (apart from the 18 lenght form). This leads to 3 genes and two alleles in each gene.
So, until now we have:
Parental) 6cm x 30cm
F1) 18 cm
Parental) 18 cm x 18 cm
F2) 6, 10, 14, 18, 22, 26, 30
Gene 1: allele A and a
Gene 2: allele B and b
Gene 3: Allele C and c
Phenotypes:
aabbcc: homozygotic recessive form
AABBCC: homozygotic dominant form
AaBbCc: heterozygotic form for every intervening gene
If the recessive form is 6cm length, and each dominant allele contributes in 4 cm to each phenotype, we get:
2) An F2 piglet with an 18 cm tail is heterozygous at each of the tail-length loci, and is mated to an F2 piglet with a 6 cm tail.
Parental) AaBbCc x aabbcc
Gametes) ABC ABc AbC Abc aBC aBc abC abc
abc abc abc abc abc abc abc abc
Punnet square)
ABC ABc AbC Abc aBC aBc abC abc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
abc AaBbCc AaBbcc AabbCc Aabbcc aaBbCc aaBbcc aabbCc aabbcc
F3 genotype and phenotype)
8/64 AaBbCc = 18 cm
8/64 AaBbcc = 14cm
8/64 AabbCc = 14cm
8/64 Aabbcc = 10cm
8/64 aaBbCc = 14cm
8/64 aaBbcc = 10cm
8/64 aabbCc = 10cm
8/64 aabbcc = 6cm
Each dominant allele contributes 4cm to the recessive homozygote form for each phenotype.
B.) The growth of spines
C.) The presence of toxins in seed casings
D.) The production of resins
Answer: Option A.
The generation of nectar in flowering cactus is not a nonspecific defensive mechanism.
Explanation:
Cactus is a xerophytes that have adaptations to survive in its environment.
Cactus have extrafloral nectaries that produce nectars for pollination.The generation of Cactus nectars is just to attract insects like bees for polloniation and not as nonspecific defensive mechanism.
wait to see if it goes lower
increase muscle activity to generate heat
add fur or fat to increase insulation
Answer: The correct answer would be increase muscle activity to generate heat.
Explanation:
Endothermic animals are those which maintain their body temperature mainly by their metabolic activity irrespective of environmental heat.
In case, there is a drop in environmental temperature then endothermic animals increase their metabolic activity and metabolize sugars and fats at a faster rate.
It release more heat and increase the body temperature.
One the various methods for increasing metabolism is increase in muscle activity such as done in shivering. Shivering increases muscle activities which increases body temperature.
An endothermic animal would increase muscular activity to generate heat in response to a sudden drop in environmental temperature. This internal heat production is part of their physiological adaptation to maintain stable body temperature in varying conditions.
When faced with a sudden drop in environmental temperature, an endothermic animal will typically increase muscle activity to generate heat. Unlike ectothermic animals, endotherms maintain a stable internal body temperature despite changes in the environment. They are capable of doing this because they generate their own heat internally, often through processes like muscular activity including shivering. Therefore, in an attempt to sustain a constant body temperature when exposed to a colder environment, muscular activity within the animal would increase to produce more heat. This, in turn, helps to counteract the cooling effect of the lower external temperatures.
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B. the Sun appears lower in the sky than during other seasons.
D. the Sun rises in the Northeast and sets in the Northwest.
On the northern hemisphere the north is to the left, the Sun rises in the east (far arrow), culminates in the south (to the right) while moving to the right and sets in the west (near arrow). Both rise and set positions are displaced towards the north in summer, and towards the south for the winter track.
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Answer:
its b
Explanation:
because days get shorter in the winter