Answer:
The delivery of the paternal genome to the egg is a primary goal of fertilization. In preparation for this step, the nucleus of the developing spermatozoon undergoes extensive morphological and biochemical transformations during spermatogenesis to yield a tightly compacted sperm nucleus. These modifications are essentially reversed during fertilization. As a result, the incorporated sperm nucleus undergoes many steps in the egg cytoplasm as it develops into a male pronucleus. The sperm nucleus (1) loses its nuclear envelope, (2) undergoes nucleoprotein remodeling, (3) decondenses and increases in size, (4) becomes more spherical, (5) acquires a new nuclear envelope, and (6) becomes functionally competent to synthesize DNA and RNA. These changes are coordinate with meiotic processing of the maternal chromatin, and often result in behaviors asynchronous with the maternal chromatin. For example, in eggs fertilized during meiosis, the sperm nucleus decondenses while the maternal chromatin remains condensed. A model is presented that suggests some reasons why this puzzling behavior exists. Defects in any of the processes attending male pronuclear development often result in infertility. New assisted reproductive technologies have been developed that ensure delivery of the sperm nucleus to the egg cytoplasm so that a healthy embryo is produced. An emerging challenge is to further characterize the molecular mechanisms that control sperm nuclear transformations and link these to causes of human infertility. Further understanding of this basic process promises to revolutionize our understanding of the mystery of the beginning of new life.
Explanation:
The delivery of the paternal genome to the egg is a primary goal of fertilization. In preparation for this step, the nucleus of the developing spermatozoon undergoes extensive morphological and biochemical transformations during spermatogenesis to yield a tightly compacted sperm nucleus. These modifications are essentially reversed during fertilization. As a result, the incorporated sperm nucleus undergoes many steps in the egg cytoplasm as it develops into a male pronucleus.
Answer:
Example of toxin; Arsenic.
How does it contribute to diabetes; overconsumption
Im not sure if this will be the answer you teacher is looking for but i think the answer would be
Hair on the head protects scalp from injury and sunlight
Eyelashes and eyebrows protect eyes
Nostril and ear hairs protect from foreign particles
D. Learned behaviors do not directly affect natural selection because they are not inherited.
This is true because learned behaviors can be taught to the offspring but do not come within them the way instincts do.
When a fish swims from salt water into fresh water its cells react by losing water and shrinking. The correct option is D.
<h3>What is fresh water?</h3>
Glaciers, lakes, reservoirs, ponds, rivers, streams, wetlands, and even groundwater contain fresh water.
These freshwater habitats cover less than 1% of the world's total surface area but are home to 10% of all known animals and up to 40% of all known fish species.
When a fish swims from salt water into fresh water its cells react by losing water and shrinking due to osmosis.
Thus, the correct option is D.
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