Only the successful competitors will reproduce, mortality<span> is very high. Four (4) conditions for natural selection. Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population.</span>
<span>The scientific method is the process by which scientists build a consistent and objective ... Formulation of a hypothesis to explain the phenomenon in the form of a causal .... The application of the scientific method is limited to independently </span>
Answer:
The correct answer is option d.
Explanation:
Based on the given question, the genotype of the male parent is aa, the genotype of the female parent is Aa, and the genotype of the offspring is AAa, showing trisomy characteristics. In the given case, the existence of two A chromosomes shows that the chromosomes non-disjunction at the time of gametogenesis have taken place in the female as she is the only one possessing A allele. Hence, it can be concluded that the disjunction is maternal in characteristic.
The duplication of chromosomes takes place at the time of the S-phase of meiosis. Thus, after going through S-phase, the karyotype of the cell will be AAaa (maternal gametogenesis), this set of the chromosome is termed as homologous pair, and the pair of AA or aa is termed as sister chromatids.
The meiotic disjunction takes place in two phases. First, in meiosis I disjunction, in this separation of homologous chromosomes takes place, that is, the maternal cell AAaa get differentiated into aa and AA daughter cells. Secondly, in meiosis II disjunction, the separation of sister chromatids takes place into two independent chromosomes, that is, the formation of two cells each comprising chromosome A from the AA cell and the formation of two cells each with chromosome a from the aa cell.
Thus, the phenomenon of non-disjunction would have taken place at the time of meiosis II in the case of a female gamete to exhibit two A chromosomes. Hence, the correct answer is option d.
Abiogenesis is the theory that life arose from non living molecules to form the earliest life forms. In the simplest sense, once there is life, life will arise from living rather than non living matter. However, there are those who speculate that it is possible for abiogenesis to occur more than once.
Stomata play an important role in photosynthesis as they allow the plant to absorb carbon dioxide from the environment. In exchange, stomata allow oxygen, which is a waste product of photosynthesis, to be released. In the process, water vapor is also lost as the internal parts of the leaves are exposed. To reduce exposure, stomata are found on the underside of the leaves. They are protected from the sun as excessive heat can increase the rate of water vapor leaving and thus wither the plant. Stomata also have guard cells around the epidermis that close when too much water is being lost.
