Answer:
Because the F1 plants all had a lowercase a/short plant allele, there was a 25% chance that two plants would contribute it to their offspring and they both did sometimes to make a aa offpsring.
Explanation:
All the F1 plants were heterozygous, so when they were crossed, the resulting genotypic ratio was 1 AA : 2 Aa : 1 aa. As you can see, this is the first time since the parent generation that there is a aa genotype and short plant phenotype, so that's why short plants reappeared.
Answer:
d.The wing-assisted incline running theory postulates that wings were initially used to maintain balance while climbing up slopes.
Explanation:
Two theories were given to explain the origin of avian flight. The top-down theory suggested that the birds' ancestors were tree dwelling species. They took help of wings to glide from tree to tree in order to avoid predator or catch prey. The bottom up theory suggested that the birds' ancestors were ground dwelling species. They took help of wings to maintain a balance and provide a lift for efficient running.
Wing-assisted incline running was a mixture of both the above theories and gave a balanced view point. According to it, birds' ancestors used wings to maintain a balance while running up inclined slopes. The wings helped them to save energy while scaling slopes and eventually a flight mechanism was also developed.
Answer:
The correct answer would be 10.
The cell cycle can be divided into four phases namely gap 1 (G₁) phase , synthesis (S) phase, gap 2 (G₂) phase, and mitosis (M) phase.
DNA (deoxyribonuceic acid) content is only replicated and doubled in the S phase. However, the chromosome number remains the same. It can be explained as the number of chromosomes remains the same (2n) but number of chromatids doubles (4n) after S phase.
The number of chromatids restores to 2n in daughter cells after completion of mitosis.
Hence, if number of chromatids in metaphase was 20 i.e. 4n then the number of chromosomes (2n) would be 10.
Hence, 10 chromosomes or 5 pairs of chromosome would be present in the cell during its G₁ phase.
The answer is B since the energy that the body uses or the energy we have is measured in calories.
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I believe the answer is PREZYGOTIC isolating mechanisms
