Protostomes develop a mouth first and then an anus. This is the difference between protostomes and deuterostomes.
In protostome development, there is a spiral radical and indeterminate cleavage. The blastopore becomes the mouth and the coelom forms from the mesoderm.
In deuterostomes development, radial and indeterminate cleavage takes place. The blastopore is the new anus and the coelom forms from budding off the wall of the archenteron.
Answer:
Frequency of B allele is 0.6681
Explanation:
If p represents the frequency of dominant allele and q represents the frequency of recessive allele, according to Hardy-Weinberg equilibrium:
p + q = 1
p² + 2pq + q² = 1
where p² = frequency of homozygous dominant genotype
q² = frequency of homozygous recessive genotype
2pq = frequency of heterozygous genotype
Given that number of recessive chestnut horse = 28
Total horses = 226 + 28 = 254
frequency of b² genotype = 28/254 = 0.1102
frequency of recessive b allele = √0.1102 = 0.3319
So, frequency of B allele =
1 - 0.3319 = 0.6681
Hence frequency of B allele is 0.6681
Answer:
B. Multipotent cells
Explanation:
Multipotent stem cells are the one that develops from pluripotent stem cells during embryonic development. The multipotent stem cells are the stem cells which have specific functions. These cells develop into specific cell types to replace the older cells.
For example, keratinocytes are the multipotent cells of the skin that produce new skin cells. Spermatogonia are the multipotent cells present in testes so that they can form sperms.
The correct answers are evolution, genetic mutation and selection.
The early ancestors of horses showed the pressence of digits and now the modern horses have hooves in their limbs. There could be many reasons for the pressence of hooves horses.
These could be due to the genetic mutations, which could have changed the shape of the digits in the limb. Sudden change in DNA can cause mutation and this mutation can change the phenotype of the horse.
There are chances that evolution took place over a period of time that changed the character in the horse.
Natural selection can also be one of the reason for the change in the phenotype of the digits on the limb of the horses.
Answer:. Nondisjunction during meiosis I in either the male and female gamete
The failure of homologous chromosome to separate at mitosis, or failure of sister chromatids to separate at Anaphase of meiosis I or ii is called non-disjunction.
In this cell division anomaly the unsegregated chromosomes are separated into cells as single chromosomes, therefore extra copies are therefore inherited.This result is one of the cell having an extra copies of chromosomes than others( chromosomes 21.
If this extra chromosome copies is segregated into a sperm or egg, the resulting zygote cells will have extra copy as chromosome 21, and hence Down syndrome.
→It is more common in Meiosis 1 than ii,because of longer duration of the first stage of division than meiosis ii,given rooms to errors.
→Most common in women(with age increase) than men because of exchange of telomeres in them,which worsen with age. Their Meiotic mechanism which weaken with age, and more prone to errors compare to men,
Explanation:
