Answer:
Sperm-egg interaction
Explanation:
The formation of fertilization envelope is well-studied on the model system- sea urchin. It has been shown that, the fertilization envelope is formed after the initial sperm-egg interaction from the egg surface vitelline envelope and the paracrystalline protein fraction which is derived from cortical granules. Secretion from cortical granules, prevents polyspermy.
The evolution of sexual reproduction is a great puzzle in modern evolutionary biology. Many groups of eukaryotic organisms, especially most animals and plants, reproduce sexually. The evolution of sex between two organisms of the same species contains two related but different themes: its origin and its maintenance. However, since hypotheses for the origin of sex are difficult to test experimentally, most of the current work has focused on the maintenance of sexual reproduction. Biologists, including W. D. Hamilton, Alexei Kondrashov, and George C. Williams, have proposed various explanations for how sexual reproduction is maintained in a large set of different living things.
<span>Nurses who are pregnant or could become pregnant should not handle finasteride and dutasteride if they are broken or crushed due to the high risk of abnormal growth that can occur to male fetus.</span>
The organ which plays the primary role in prompting individuals to seek food is the brain. The brain is one of the most important organ of the nervous system. It is comparable to the CPU of a computer. It is repsonsible of processing information that it is receiving from all the senses and send the message back to the organs for a response.
Answer:
<em>Ana-phase 1 of Meiosis 1 in Male Parent...</em>
Explanation:
It is clear that meiosis is only happening in male due to AAa nondisjuction of dominant AA from male parent. The disjunction is occuring during spermato-genesis during Ana-phase 1 of Meiosis 1 cause it is only possible explanation of tri-somy at Chromosome 1...
