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3 years ago

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Which of the following statements about the ice ages is true? a. An ice age will never come again. b. The causes of ice ages are

well known. c. During the ice ages, icy glaciers covered much of the continents. d. There were no living organisms during the ice ages.

1 answer:

zaharov [31]3 years ago

4 0

Answer:

C

Explanation:

its a fact and in Biology we take facts over expectations

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4 years ago

Arte-miy333 [17]

Assuming diallelic genes, that express complete dominance, and assort independently, <em>1) </em><em>Genotypic ratio</em><em>=1:2:1. </em><em>Phenotypic ratio</em><em>=3:1 </em><em>/</em><em> 2) </em><em>Parental genotype</em><em>: PpRr. </em><em>Gametes</em><em>= PR, Pr, pR, pr. </em><em>Phenotypic ratio</em><em>: 9:3:3:1</em>

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We will assume diallelic genes that express complete dominance. In cases where two or more genes are involved, we will assume they are not linked, and alleles assort independently.

1) <u>FRECKLES</u>

F is the dominant allele that codes for freckles

f is the recessive allele that codes for no-freckles

Cross: Between a mother and a father who both have freckles and are heter0zyg0us for the trait

Parentals) Ff x Ff

Gametes) F f F f

Punnett square) F f

F FF Ff

f Ff ff

F1) Genotype

1/4 = 25% of the progeny is expected to be h0m0zyg0us dominant, FF

2/4 = 1/2 = 50% of the progeny is expected to be heter0zyg0us, Ff

1/4 = 25% of the progeny is expected to be h0m0zyg0us recessive, ff

Phenotype

3/4 = 75% of the progeny is expected to express freckles, FF + Ff

1/4 = 25% of the progeny is expected to not express freckles, ff

Genotypic ratio ⇒ 1:2:1

Phenotypic ratio ⇒ 3:1

2) <u>FLOWER COLOR AND SEED SHAPE</u>

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P is the dominant allele that codes for purple flowers

p is the recessive allele that codes for white flowers

R is the dominant allele that codes for round seeds

r is the recessive allele that codes for wrinkled seeds

Cross: Between two plants that are heter0zyg0us for flower color and seed shape

Parentals) PpRr x PpRr

Gametes) PR, Pr, pR, pr PR, Pr, pR, pr

Punnett square) PR Pr pR pr

PR PPRR PPRr PpRR PpRr

Pr PPRr PPrr PpRr Pprr

pR PpRR PpRr ppRR ppRr

pr PpRr Pprr ppRr pprr

F1) Genotype

1/16 individuals are expected to be PPRR

2/16 individuals are expected to be PPRr

1/16 individuals are expected to be PPrr

2/16 individuals are expected to be PpRR

4/16 individuals are expected to be PpRr

2/16 individuals are expected to be Pprr

1/16 individuals are expected to be ppRR

2/16 individuals are expected to be ppRr

1/16 individuals are expected to be pprr

Phenotype

9/16 individuals are expected to have purple flowers with round seeds, PPRR + PpRR + PPRr + PpRr

3/16 individuals are expected to have purple flowers and wrinckled seeds, PPrr + Pprr

3/16 individuals are expected to have white flowers and round seeds, ppRR + ppRr

1/16 individuals are expeceted to have white flowers and wrinckled seeds, pprr.

Phenotypic ratio ⇒ 9:3:3:1

Genotype of parent plant 1: PpRr

Gamete 1: PR
Gamete 2: Pr
Gamete 3: pR
Gamete 4: pr

Genotype of parent plant 2: PpRr

Gamete 1: PR
Gamete 2: Pr
Gamete 3: pR
Gamete 4: pr

<u> PHENOTYPE GENOTYPE </u>

purple flowers, round seeds: PPRR, PpRR, PPRr, PpRr

purple flowers, wrinkled seeds: PPrr, Pprr

white flowers, round seeds: ppRR, ppRr

<u>white flowers, wrinkled seeds: pprr </u>

<u> PHENOTYPE NUMBER </u>

purple flowers, round seeds: 9

purple flowers, wrinkled seeds: 3

white flowers, round seeds: 3

<u>white flowers, wrinkled seeds: 1 </u>

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You can learn more about monohybrid and dihybrid crosses at

brainly.com/question/1185199?referrer=searchResults

brainly.com/question/24076691?referrer=searchResults

brainly.com/question/2669862?referrer=searchResults

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3 years ago

What phase of development gets its name from the greek word for “swelling”?

Yakvenalex [24]

The answer to this question would be embryonic phase.

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