A mystery emerged in Britain during the 1800s. An Industrial Revolution had just taken hold. Busy factories started to darken the skies with smoke from burning wood and coal. The sooty pollution blackened tree trunks. In short order, Victorian scientists took note of a change, too, among peppered moths (Biston betularia). A new, all-black form emerged. It came to be called B. betularia carbonaria, or the “charcoal” version. The older form became typica, or the typical form.

Birds had been able to easily spot the old-style, lightly colored peppered moths as they settled onto soot-blackened tree trunks. Their new dark cousins instead blended in. The result: those carbonaria were less likely to be eaten.

Not surprisingly, numbers of light-colored moths started to fall as their dark cousins increased. By 1970, in some polluted regions nearly 99 percent of peppered moths were now black.

Source

What process caused changes in the frequency of traits within the peppered moth population?


A artificial selection


B sexual reproduction

C natural selection

D mutation

Answer:

The velocity of the red  go-kart after the collision is 3 m/s

Explanation:

Here the principle of conservation of momentum will be used.

Momentum of the system before collision = Momentum of the system after collision

Momentum of the system before collision [tex]= 2*5 + 2*0[/tex]

Momentum of the system after collision [tex]= 2 * 2 + 2 *x[/tex]

[tex]2*5 + 2*0[/tex] [tex]= 2 * 2 + 2 *x[/tex]

[tex]10-4 = 2 x\\6 = 2x\\x = 3[/tex]m/s

The velocity of the red  go-kart after the collision is 3 m/s

Answer:

false : In distance time graph,time is shown on the x -axis

Answer:

B. x = 50, Y = 100 ,Z= 150

sorry if it's wrong

Answer:14C

Explanation:

Translate : Physically, a stone is dropped into a well and after 10 seconds you can hear the crash against the bottom, if the speed?

Answer : 383 m

Answer:

108 v

Explanation:

Answer:

No.

Explanation:

Para darnos cuenta de esto tenemos que pensar en lo siguiente:

Pensemos en un vaso de vidrio, lleno de agua hasta la mitad, la otra mitad puede ser manteca derretida

Si metemos el vaso en la heladera durante un par de horas, (sabemos que la manteca en la heladera se mantiene sólida) veremos que la manteca se solidificó en la parte de arriba, mientras que el agua sigue líquida.

Entonces encontramos dos compuestos con distintas temperaturas para cambio de fase, pero materiales es más específico, y puede referirse a materiales puros.

Entonces vamos a dos metales:

Primero tenemos una pieza de hierro y una de mercurio en el congelador (supongamos que ambas están a 0°C).

Ahora los sacamos del congelador y los dejamos llegar a temperatura ambiente.

Como bien sabemos, el mercurio es líquido a temperatura ambiente, entonces el mercurio va a sufrir un cambio de fase

Ahora pensemos en el hierro; claramente va a seguir siendo sólido a temperatura ambiente, entonces podemos ver dos materiales cuyo cambio de fase de sólido a líquido ocurre en distintas temperaturas, por lo que podemos concluir que no, la temperatura de cambio de estado no puede ser igual para todos los materiales, y esto se debe a que la estructura atómica de todos los materiales es diferente.

Answer:

1.11

Explanation:

The index of the medium can be calculated using below formula

V= c/ n ............eqn(1)

Where V= velocity of the light is reduced to while traveling through the second medium= 2.7 x 10^8 m/s

n= index of the medium

c= speed of light= 3 x 10^8 m/s

Substitute for the values in eqn(1)

2.7 x 10^8 = (3 x 10^8 m/s)/ n

Making " n" subject of the formula, we have

n= (3 x 10^8 )/(2.7 x 10^8)

n= 1.11

Hence, the index of the medium is 1.11

We have that  the Time  it took him to reach that speed is

t=1.2sec

From the question we are told

A runner at the start of a race generates 250 W of power as he accelerates to 5 m/s. If the runner has a mass of  60 kg, how long did it take him to reach that speed?

Generally the equation for the   is mathematically given as

[tex]P=W/t[/tex]

Therefore

[tex]W=Pt\\\\W=250*t[/tex]

Where

[tex]W=f*d\\\\5*60=250*t\\\\t=\frac{5*60}{250}]\\\\t=1.2sec[/tex]

Therefore

Time  it took him to reach that speed is

t=1.2sec

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Answer:

Without any external forces a moving object will continue to move in a straight line. The gravitational force between the two objects will provide the centripetal force to keep the objects moving around one another.

1. satellite in orbit around the earth             (motion of earth is negligible)

2. moon in orbit around the earth     (center of motion several thousand miles        

                                                             from center of earth)

3. earth in orbit around sun    (center of rotation close to center of sun)

4. binary stars         (if masses of stars are equal center of rotation is in middle)

Halogens are highly reactive nonmetal elements in group 17 of the periodic table. ... Halogens are among the most reactive of all elements. They have seven valence electrons, so they are very “eager” to gain one electron to have a full outer energy level.

Answer:

O. Geologists and archaeologists use different dating processes to determine the age of rocks, fossils, and ancient artifacts.

Explanation:

Redioactive decay is the process whereby the radioactive materials reduces in quantity through the decay of its materials.

For example, if there where 100g of polonium today, and 5 years later, it has reduced to 30g, then, radioactive decay has taken place over the long period of time.

One of its major use is in the determination of the ages of rocks, fossils, and ancient artifiacts through its cabon dating inorder to determining the radioactive decay of those materials over the past few decades.

Answer:

Tiene que patear el balón cerca del nivel del suelo para conseguir el gol.

Explicación:

Leo Messi necesita patear el balón no en el aire, en el nivel del suelo para poder meter el gol para el equipo. Delante del fútbol hay muchos jugadores del equipo contrario dispuestos a detener el tiro libre de Leo Messi. Cuando Leo Messi patea el balón en el aire, los jugadores también saltan en el aire para detener el tiro libre que atraviesa la cabeza y para conseguir el gol Leo Messi tiene que evitar patear el balón en el aire y patear el balón cerca del nivel del suelo. que puede atravesar a los jugadores oponentes cuando lo saltan para detener el balón a través de sus cabezas para que el balón pase por debajo de sus pies y llegue a la portería.

Answer: 8v

Explanation:

The total voltage drop across the first and second resistor is 8 V, hence option A is correct.

Voltage is the fluctuation in electric potential between the two places. It is sometimes produced by electric pressure, electric tension, or voltage source. The work required to move a test charge between two places in a static electric field corresponds to this. The derived measure for voltage in the International System of Units is called a volt. Work per unit energy is expressed in SI units as joules per coulomb, with 1 volt equaling 1 joule per 1 coulomb.

To detect the voltages between two locations in a circuit, use a voltmeter. A common reference point, like the system's foundation, is frequently utilized as one of the points.

A voltage can indicate either a supply of energy or its loss, dissipation, or storage.

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Answer:The greater the density of a medium, the slower the speed of sound. This observation is analogous to the fact that the frequency of a simple harmonic motion is inversely proportional to m, the mass of the oscillating object. The speed of sound in air is low, because air is easily compressible.

Explanation:

Answer:

antinode i'm pretty sure :) hope this helps

Explanation:

Answer:

b. antinodes

Explanation:

Answer:

200W

Explanation:

W=F*d

P=W/t

P=(100)(10)/5

P=200

Answer:

D. Numbers of atoms

Explanation:

The feature of the components of matter that only stays the same in chemical reactions is: D. numbers of atoms.

The law of conservation of matter (LOCOM) states that mass can neither be created nor destroyed in any chemical reaction.

This ultimately implies that, a balanced chemical equation would always require the same number of atoms on both the reactant side and product side of a chemical reaction.

In conclusion, we can deduce that the feature of the components of matter that only stays the same in chemical reactions is: D. numbers of atoms.

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Answer:The greater the amount of water that there is it will take longer for the water to freeze because more heat has to be dissipated into the environment

Explanation:

Answer:

The greater the mass of water, the more heat has to be dissipated into the environment and the longer it will take to freeze. The greater the surface area of the water, the faster the water will lose its heat and freeze.

Answer:

ac = 72 m/s²

Fc = 504 N

Explanation:

We can find the centripetal acceleration of the hammer by using the following formula:

[tex]a_c = \frac{v^2}{r}[/tex]

where,

ac = centripetal acceleration = ?

v = constant speed = 12 m/s

r = radius = 2 m

Therefore,

[tex]a_c = \frac{(12\ m/s)^2}{2\ m}[/tex]

ac = 72 m/s²

Now, the centripetal force applied by the athlete on the hammer will be:

[tex]F_c = ma_c\\F_c = (7\ kg)(72\ m/s^2)[/tex]

Fc = 504 N

Answer:B

Explanation:

Answer:

(c) 2

Explanation:

Heat transfer across the walls due to conduction is given by:

[tex]q = -KA\frac{\Delta T}{L}[/tex]

where,

q = heat transfer rate

K = thermal conductivity

A = Area

ΔT = change in temperature

L = thickness

For wall A:

[tex]q_A = -K_AA\frac{\Delta T}{L_A}[/tex]

For wall B:

[tex]q_B = -K_BA\frac{\Delta T}{L_B}[/tex]

Because the change of temperature and area of walls are the same. Dividing both terms:

[tex]\frac{q_A}{q_B} = \frac{\frac{K_A}{L_A} }{\frac{K_B}{L_B}}\\\\ \frac{q_A}{q_B} =\frac{\frac{K_A}{K_B} }{\frac{L_A}{L_B}}[/tex]

using values given in the question:

[tex]\frac{q_A}{q_B} = \frac{4}{2}\\\\\frac{q_A}{q_B} = 2[/tex]

Therefore, the correct answer is:

(c) 2

Answer:

Protium

Explanation: Protium is an isotope of hydrogen that is composed of one proton and one electron. It is the most abundant form of hydrogen.

Answer:

To be honest. I think all three of them are hydrogen i know Deuterium and Tritium are so I decided to research about protium and it said its also hydrogen.

Explanation:

Protium Deuterium and Tritium are all isotopes of hydrogen

Answer:

Explanation:

When a substance is heated the average kinetic energy of molecules increases and they start moving with an increased speed.As a result between mean separation between the molecules also increases

Answer:

Assume I1 = Io * T1        transmission proportional to thickness

I2 = Io * T2          I is intensity of light absorbed     (3/8 absorbed)

I1 / I2 = T1 / T2

T2 = T1 * (I2 / I1) = 2 * (2/3 / 3/8) = 2 * 16/9 = 32/9   thickness for 2/3 absorbed

The length of the beaker when the transmittance is changed to one-third is 13.78 cm.

The given parameters;

To find:

The length of the beaker is calculated by applying Beer-Lambert law;

[tex]\frac{I}{I_o} = e^{-cl}[/tex]

[tex]\frac{I_1}{I_0} = e^{-cl_1} = \frac{3}{8} \ ----(1)\\\\\frac{I_2}{I_0} = e^{-cl_2}= \frac{1}{3} \ ---- (2)[/tex]

divide equation (1) by equation (2);

[tex]\frac{e^{-cl_1}}{e^{-cl_2}} = \frac{3}{8} \times \frac{3}{1} \\\\ (c \ is \ constant \ for \ both) \\\\e^{-l_1 + l_2} = \frac{9}{8} \\\\l_2 - l_1 = ln(\frac{9}{8} )\\\\l_2 - 0.02 = 0.1178\\\\l_2 = 0.1178 + 0.02\\\\l_2 = 0.1378 \ m\\\\l_2 = 13.78 \ cm[/tex]

Thus, the length of the beaker when the transmittance is changed to one-third is 13.78 cm.

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Answer:

Explanation:

For A to become positively charged, a + charge must transfer from B to A.

The charge that must transfer for object A to become positively charged is the negative charge in object A.

Charging by conduction occurs when a charged object causes the flow of electron when it comes in contact with an uncharged object.

An object can either be negatively or positively charged. An object is said to be positively charged when it contains more protons than electron.

Therefore, for object A to be positively charged, the charge that must transfer for object A to become positively charged is the negative charge.

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