Answer:
Directly counting blood cells or tissue cells by using a hemocytometer can determine the concentration of a known volume. Counting the number of colonies that arise on a pour plate can calculate the concentration by multiplying the count by the volume spread on the pour plate.
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:
I hope this helped!
SE LE CONOCE COMO IRRITABILIDAD
Los seres vivos tienen la capacidad de responder a una variedad de estímulos tanto del medio exterior como del medio interno. Esta capacidad de respuesta se denomina irritabilidad, porque es diferente a otro tipo de respuestas que se observan en la naturaleza.
Q1. The answer is 1.
It can be calculated using the equation:
(1/2)ⁿ = x
x - decimal amount remaining,
n - a number of half-lives.
x = 50% = 50/100 = 0.5
n = ?
(1/2)ⁿ = 0.5
log((1/2)ⁿ) = log(0.5)
n * log(1/2) = log(0.5)
n * log(0.5) = log(0.5)
n = log(0.5)/log(0.5)
n = 1
Q10. The answer is 2.
It can be calculated using the equation:
(1/2)ⁿ = x
x - decimal amount remaining,
n - a number of half-lives.
Rhyolite #2 has 25% of the parent H remaining:
x = 25% = 25/100 = 0.25
n = ?
(1/2)ⁿ = 0.25
log((1/2)ⁿ) = log(0.25)
n * log(1/2) = log(0.25)
n * log(0.5) = log(0.25)
n = log(0.25)/log(0.5)
n = -0.602 / - 0.301
n = 2
Q3. The answer is 100 million years.
A number of half-lives (n) is a quotient of total time elapsed (t) and length of half-life (H):
n = t/H
n = 1
t = ?
H = 100 000 000 years
n = t/H
t = n * H
t = 1 * 100 000 000 years
t = 100 000 000 years<span>
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<span>Virtual team is composed of individuals who are separated geographically but linked by communications technology.
</span><span>The communications technologies that are used in order the people to work include e-mail, Skype, video conferencing..
</span><span>When employees work with technology via electronic, telecommunications, and Internet means it is referred to as telework.
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