Answer:
The most common elements, like carbon and nitrogen, are created in the cores of most stars, fused from lighter elements like hydrogen and helium. The heaviest elements, like iron, however, are only formed in the massive stars which end their lives in supernova explosions.
Explanation:
Answer:
a. heart development.
Explanation:
As the third week of fetal development starts, the process of formation of blood vessels begins. Also, the splanchnic mesoderm in the head end of the embryo forms heart on days 18 and 19. Since it develops heart, this part of the mesodermal cells is called the cardiogenic area. The underlying endoderm sends the induction signals to these mesodermal cells to form a pair of endocardial tubes that gradually develop into a single primitive heart tube.
This primitive heart begins to beat by the end of the third week of development. Therefore, any drug that affects fetal development during the first 20 days of the pregnancy might affect the development of the heart.
En resumen, para que se defina y aborde de manera operativa, el "gen mendeliano" requiere una diferencia de fenotipo asociada con una diferencia de genotipo, mientras que el "gen molecular" requiere transcripción.Answer:
Explanation:
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Answer:
The transfer of mature pollen grain from anther of the flower to the stigma of the same flower of the same [species is called self pollination.
Generally, the transfer of pollen grains by wind,animals,and water to stigmas is called pollination. It is a means of vegetative propagation which ensures reproduction.
Therefore during self pollination, the same genes are distributed from one generation to another. Thus genetic purity is ensured. It also ensured reproductive success. because there is little chance of the pollen grain getting lost in transit. It is also certain a particular plant would always breed true.
Additionally it prevent the process of transfer of genes in some transgenic crops( rice, maize) where through genetic engineering some genes are introduced in their genome.
The only negative effect is lack of genetic diversity. Therefore after a period of time the plants get weak and prone to diseases and infection. Because of poor resistant from lack of variation.
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