The randomness in the alignment of recombined chromosomes at the metaphase plate, coupled with the crossing over events between nonsister chromatids, are responsible for much of the genetic variation in the offspring. To clarify this further, remember that the homologous chromosomes of a sexually reproducing organism are originally inherited as two separate sets, one from each parent. Using humans as an example, one set of 23 chromosomes is present in the egg donated by the mother. The father provides the other set of 23 chromosomes in the sperm that fertilizes the egg. Every cell of the multicellular offspring has copies of the original two sets of homologous chromosomes. In prophase I of meiosis, the homologous chromosomes form the tetrads. In metaphase I, these pairs line up at the midway point between the two poles of the cell to form the metaphase plate. Because there is an equal chance that a microtubule fiber will encounter a maternally or paternally inherited chromosome, the arrangement of the tetrads at the metaphase plate is random. Thus, any maternally inherited chromosome may face either pole. Likewise, any paternally inherited chromosome may also face either pole. The orientation of each tetrad is independent of the orientation of the other 22 tetrads.
Explanation:
Lithified ash (or ash mixed with pyroclastic fragments) forms a volcaniclastic rock called a Tuff.
- A form of rock called tuff is created when volcanic ash is blasted from a vent during an eruption.
- The ash is transformed into a rock after ejection and deposition. Tuff is defined as rock with an ash content of more than 75%, whereas tuffaceous refers to rock with an ash content of 25% to 75%.
- The thickness of tuff often decreases with distance from the volcano and is usually greatest close to the volcanic vent. The typical shape of a tuff deposit is that of a "lens," not a "layer."
- Tuff may also be thickest on the vent's side that faces away from the wind or on the side facing the direction of the blast.
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Answer:
13 is the answer for both
Explanation:
The atomic number is also the atoms count of protons and electrons when the element is of a neutral charge.
