Mitosis is a process of cellular division resulting in a single cell splitting into two identical cells.
The sequence of events is as follows:
(1) Prophase
<span>(a) During the early prophase, cells begin to disassemble some components and construct others. This phase prepares for chromosome division.</span><span>(b) In prometaphase, the mitotic spindle starts organizing and seizing the chromosomes.
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(2) Metaphase
<span>All chromosomes are captured by the spindle, which aligns them along the cell's center, prepping for division.
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(3) Anaphase
<span>The sister chromatids are pulled apart and migrate to opposite ends of the cell.
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(4) Telophase
<span>The division of the cell is nearly complete, and it begins to reorganize its normal internal structures while cytokinesis occurs.</span>
Embryological evidence
Explanation:
Deuterostomes include echinoderms, hemichordates, and chordates. Despite their diverse body structures, they all feature a mouth that forms secondarily during embryonic development, thought to be a derived evolutionary trait connecting a common ancestor to all its descendants (a synapomorphy). This mouth originates from the ectoderm layer through invagination opposite the blastopore in the gastrula.
Regardless of the external conditions of the cell
Answer:
Options B, C, and D
Explanation:
The following assertions are accurate about the continental crust:
Its thickness ranges from 25 to 70 km.
It comprises various kinds of rocks.
This layer contains silicate minerals rich in sodium, potassium, aluminum, and calcium.
Answer:
Constructing phylogenetic trees using molecular data
A transformative tool for phylogenetic analysis is DNA sequencing. This method allows us to compare the sequences of orthologous (evolutionarily related) genes or proteins instead of relying solely on the physical or behavioral traits of organisms.
The fundamental concept behind such comparisons is akin to our previous discussion: there is a common ancestor for the DNA or protein sequence, and it may have undergone changes throughout evolutionary history. However, a gene or protein isn't limited to a singular characteristic that exists in two forms.
Instead, every nucleotide in a gene or each amino acid in a protein can be considered an individual feature that can mutate into multiple forms (e.g., A, T, C, or G for nucleotides). Thus, a gene consisting of 300 nucleotides could be interpreted as having 300 distinct features present in 4 states. The data gleaned from sequence analyses—and consequently, the detail we can achieve in a phylogenetic tree—is significantly greater than when we analyze physical characteristics.
To interpret sequence data and uncover the most likely phylogenetic tree, biologists often employ computer software and statistical algorithms. Generally, when sequences of a gene or protein are compared among species:
A larger count of variations indicates less related species
A smaller count of variations indicates more closely related species
