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3 years ago

A star is born whenever a nebula expands.

Biology

2 answers:

IgorC [24]3 years ago

8 0

Answer:

False.

Explanation:

The birth of a star occurs when when a nebula starts to contract (and not to expand). Due to gravitational instabilities, the nebula can fragment into smaller pieces that, in turn, can also collapse and continue to divide, eventually forming tens or hundreds of stars. As they start to contract, these fragments start a heating phase and are called protostars. When the temperature in the center of the fragments reaches a value high enough to start the nuclear fusion reaction, the contraction stops and the star is born.

arlik [135]3 years ago

6 0

A star is born whenever a nebula expands.
This is false.

A star is born when another star gets old from the remains of that a new star is born. <span />

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Movement of any particle or molecule from higher concentration to lower concentration is called

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3 years ago

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A particular species of bacteria has a "a generation time" of 20 minutes. That is, every 20 minutes a single bacterium completes

timofeeve [1]

Answer:

Number of bacteria cells = 2621440 cells

Explanation:

The generation time of a bacteria specie is the time it takes for a population of bacteria to double in number. The generation time for most common bacteria is quite short, about 20 minutes to 1 hour.

Bacteria reproduce asexually by binary fission, in which the parent cell divides into two to produce two identical daughter cells.

In the given question, the generation time of the bacterial species is 20 minutes.

The time that have passed from between the time the sandwich was packed at 6:00 am to lunch time by 12:00 pm is 6 hours.

Using the given formula in the hint: number of cells = 2^(ab) × C

Where a = number of times per hour the bacteria reproduces; b = number of hours; C = number of bacteria at the start

a = 60 minutes/ 20 minutes = 3; b = 6; C = 10

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3 years ago

Regression analysis is:

Ksivusya [100]

Answer: Option A.

Explanation:

Regression analysis is a statistical model for estimating the relationships among different variables.

Regression analysis helps to predict the value of the dependent variable which changes when any one of independent variables varies, while other independent variables remain fixed.

Generally Regression analysis are classified in linear and non-linear regression.

Hence, the correct option is A.

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3 years ago

ermentation reactions A. completely oxidize glucose to carbon dioxide and water B. often require the reactions of glycolysis to

goldenfox [79]

Answer:

E. two of the above are correct

Explanation:

Fermentation reactions are processes that occur without the presence of oxygen and promote the release of energy (ATP) anaerobically. For these reactions to occur, glycolysis and reduction of pyruvate must occur.

These reactions allow the regeneration of NAD + that is necessary for the breakdown of glucose during the process called glycolysis, which is primarily responsible for the production of ATP. NAD + is regenerated from NADH.

With that, we can conclude that the correct options are:

B. often require the reactions of glycolysis to provide energy as ATP

C. supply NAD for the oxidation of glucose

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3 years ago

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Dafna11 [192]

Metallic luster is your answer

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