Answer:
Genes coding for proteins involved in chiasma formation.
Explanation:
Chiasma is the connecting link between two non sister chromatids from homologous chromosomes. At chiasma chromosomal crossover takes place in which the genetic material is exchanged between the chromatids. During meiosis aneuploidy occurs if chiasma is absent or impaired due to a mutation in genes encoding for proteins involved in chiasma formation.
Aneuploidy is characterised by presence of abnormal number of chromosomes in cells. They can be 45 or 47 in number apart from the usual 46. Due to impaired chiasma, chromosome pair fails to separate and is passed on to the egg or sperm as it is hence there is one gamete with an extra chromosome and one gamete with a less chromosome. Aneuploidy can result in many genetic disorders like three copies of chromosome 21 can result in Down syndrome.
Answer:
c) The species underwent punctuated equilibrium
e) The species’ environment underwent a dramatic change for which it was poorly suited
Explanation:
Answer:
Unlike the queen bee, which has 32 chromosomes, drones have half the chromosomal charge (n= 16), so they are considered haploid.
Explanation:
The system of determination of the sex in the bees —like in other insects— is called haplodiploidy, and consists of which the females of the species possess complete charge of chromosomes, whereas the males only possess half. This is what happens with the queen bee with 32 chromosomes, while drones only have 16 chromosomes, so they are considered haploid.
Additionally, as a characteristic of haplodiploidy, males only proceed from female gametes, so they can only contribute gametes to produce females of the species.
The other options are not correct because:
- <em>Drones, with half of the chromosomal charge, </em><u><em>cannot be diploid</em></u><em>.
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- <u><em>Monosomy and trisomy</em></u><em> are defects in the distribution of chromosomes during meiosis, which imply one chromosome less or one chromosome more in the normal chromosome charge respectively.</em>
bacteria are classified as microbes
The development of seeds are considered to one of the most important in the evolution of land plants especially the spore-bearing vascular plants. The seeds will serve as the alternative means of dispersal for reproduction purposes especially in areas where there is no water.
