Answer:
Main sequence stars fuse hydrogen atoms to form helium atoms in their cores. About 90 percent of the stars in the universe, including the sun, are main sequence stars. These stars can range from about a tenth of the mass of the sun to up to 200 times as massive.
Stars start their lives as clouds of dust and gas. Gravity draws these clouds together. A small protostar forms, powered by the collapsing material. Protostars often form in densely packed clouds of gas and can be challenging to detect.
"Nature doesn't form stars in isolation," Mark Morris, of the University of California at Los Angeles (UCLS), said in a statement. "It forms them in clusters, out of natal clouds that collapse under their own gravity."
Smaller bodies — with less than 0.08 the sun's mass — cannot reach the stage of nuclear fusion at their core. Instead, they become brown dwarfs, stars that never ignite. But if the body has sufficient mass, the collapsing gas and dust burns hotter, eventually reaching temperatures sufficient to fuse hydrogen into helium. The star turns on and becomes a main sequence star, powered by hydrogen fusion. Fusion produces an outward pressure that balances with the inward pressure caused by gravity, stabilizing the star.
How long a main sequence star lives depends on how massive it is. A higher-mass star may have more material, but it burns through it faster due to higher core temperatures caused by greater gravitational forces. While the sun will spend about 10 billion years on the main sequence, a star 10 times as massive will stick around for only 20 million years. A red dwarf, which is half as massive as the sun, can last 80 to 100 billion years, which is far longer than the universe's age of 13.8 billion years. (This long lifetime is one reason red dwarfs are considered to be good sources for planets hosting life, because they are stable for such a long time.)
Explanation:
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Answer:
Uno de los progenitores es heterocigoto para color naranja (Nn) y el otro parental es homocigoto recesivo para gris (nn). Al haber una cruza entre un homocigoto recesivo y un heterocigoto, la 50% de la progenie expresa color naranja (Nn), mientras que el otro 50% expresa color gris (nn).
Explanation:
<u>Datos disponibles:</u>
- Cruce entre peces naranjas y peces grises
- 50% de la F1 son peces grises
- Naranja dominante sobre gris
Podemos nombrar el alelo dominante para color naranja <em>N</em>, y al alelo recesivo para color gris <em>n</em>.
Para que en un cruce entre dos fenotipos distintos, el 50% de la primer camada exprese uno de estos fenotipos, entonces uno de los parentales debe ser heterocigoto, mientras que el otro parental debe ser homocigoto recesivo. De esta forma 50% de la primera generación expresara uno de los fenotipos, mientras que el otro 50% expresará el otro fenotipo.
Supongamos que uno de los parentales lleva el genotipo <em>Nn</em>, y el otro parental es <em>nn</em>.
Cruce:
Parental) Nn x nn
Gametas) N n n n
Fenotipos) Naranja Gris
Cuadro de Punnett) N n
n Nn nn
n Nn nn
F1) 2/4 = 1/2 = 50% de la progenie tendrá genotipo heterocigoto, Nn
2/4 = 1/2 = 50% de la progenie tendrá genotipo homocigota recesivo,
nn
50% de la progenie será color naranja (Nn)
50% de la progenie será color gris (nn)
A ruler will not be needed due to having a graduated cylinder which can help measure the volume of liquids
Answer:
"Energy flows in one direction, matter recycles."
Explanation:
Matter "returns" to the environment by the deutucators. Energy comes from the sun and is transmitted to higher trophic structures.
