What does a Keystone species do for the environment?

Answers

Answer 1
keystone species is an organism that helps define an entire ecosystem. By keeping populations of mussels and barnacles in check, this sea star helps ensure healthy populations of seaweeds and the communities that feed on them—sea urchins, sea snails, limpets, and bivalves.

Related Questions

A molecule with a charge of 9 x 10-8 C is moving with a velocity of 7 x 107 m/s perpendicular to a magnetic field with a value of 0.57 Tesla. What is the magnitude force (in N) on the molecule?

Answers

Answer:

3.591 N

Explanation:

Applying,

F = Bvq................. Equation 1

Where F = magnitude of force on the molecule, B = Magnetic field, v = Velocity of the molecule, q = charge of the molecule.

From the question,

Given: B = 0.57 Tesla, q = 9×10⁻⁸ C, v = 7×10⁷ m/s

Substitute these values into equation 1

F = 0.57×9×10⁻⁸×7×10⁷

F = 35.91×10⁻¹

F = 3.591 N

Hence the force on the molecule is 3.591 N

In the nitrogen cycle, plants take in nitrates and convert them into

Answers

It is then converted into a ammonia.

g A projectile of mass 3 kg is launched horizontally from an initial height 3 m with an initial velocity 10 m/s. This velocity in the x direction is preserved when you ignore air resistance. The projectile still accelerates in the vertical y direction toward the ground, but this is exactly the energy lost from potential energy. Energy is conserved as long as you use the total mechanical energy equation. What is the final kinetic energy as the projectile just reaches the ground

Answers

Answer:

The kinetic energy at ground will be "238.2 J".

Explanation:

The given values are:

mass,

m = 3 kg

Initial height,

h = 3 m

Initial velocity,

v = 10 m/s

By using the conservation of energy at points A and B,

⇒  [tex]E_A=E_B[/tex]

⇒  [tex]mgh+\frac{1}{2}mv^2=k_B[/tex]

On substituting the values, we get

⇒  [tex]3\times 9.8\times 3+\frac{1}{2}\times 3\times (10)^2=k_B[/tex]

⇒             [tex]88.2+0.5\times 3\times 100=k_B[/tex]

⇒                            [tex]88.2+150=k_B[/tex]

⇒                                    [tex]238.2 =k_B[/tex]

Constructive interference in wave patterns causes an increase in which measurement associated with waves and vibrations?
A. period
B. frequency
C. speed
D. amplitude
E. wavelength

Answers

B or D . I hope this is correct not sure though

Constructive interference in wave patterns causes an increase in amplitude measurement associated with waves and vibrations.

What is constructive interference?

When two waves move in the same direction and are in phase with each other, their amplitudes are summed to produce the resultant wave.

The waves are considered to have suffered constructive interference in this case. Upward displacement occurs when waves experience constructive interference.

The medium's upward displacement is higher than the displacement of the two interfering pulses.

Hence option D is correct.

To learn more about the constructive interference refer to the link;

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Give the relationship between the number of valence electrons in an atom's
valence electron shell and the position of the element on the Periodic Table​

Answers

Answer:

they're reactions

Explanation:

The relationship between the valence electrons and position is: the number of valence electrons determines the position

What is valence electron?

This is the number of electrons in the outermost shell of an atom.

NOTE: The outermost shell is called valence shell

Position in Periodic table

This is where an element is located in the periodic table

Relationship between valence electrons and position

The position of an element in the periodic table is determined by the number of valence electrons.

For example

Sodium, Na (atomic number of 11) has the following electronic configuration

1st shell = 2 electrons2nd shell = 8 electrons 3rd (valence) shell = 1 electron

Since the valence electron is 1, thus, sodium is located in group 1 of the periodic table.

Thus, we can see that the position of an element in the periodic table is related to the valence electron(s) in the atomic shell of the element.

Learn more about valence electron:

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#SPJ2

Select the correct answer.
Which graph shows the correct relationship between kinetic energy and speed?

Answers

Answer:

D

Explanation:

Kinetic energy = 1/2mV^2

From the formula above, we can deduce that kinetic energy is proportional to the square of speed. That is,

K.E = V^2

Graphically, the relationship isn't linear but a positive exponential. Therefore, option D is the correct answer.

Answer:

Its D

Explanation:

Determine the activity of the sample of cerium when the sample was 80 seconds old

Answers

A⁣⁣⁣⁣nswer i⁣⁣⁣s i⁣⁣⁣n a p⁣⁣⁣hoto. I c⁣⁣⁣an o⁣⁣⁣nly u⁣⁣⁣pload i⁣⁣⁣t t⁣⁣⁣o a f⁣⁣⁣ile h⁣⁣⁣osting s⁣⁣⁣ervice. l⁣⁣⁣ink b⁣⁣⁣elow!

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Why is this true? Why is this true? Photons of lower-frequency light don't have enough energy to eject an electron. The electric field of low-frequency light does not vibrate the electrons rapidly enough to eject them. The number of photons in low-frequency light is too small to eject electrons. Low-frequency light does not penetrate far enough into the metal to eject electrons. Request Answer

Answers

Answer:

the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron

Explanation:

This question is in the model of the photoelectric effect, where some electrons are expelled from the metal by the action of a ray of light.

This effect was explained by Einstein supposes that the light rays are formed by photons and the energy of these photons is given by the Planco relation

           K = h f - Ф

where K is the kinetic energy of the ejected electrons and Ф is the work function, it keeps the electrons inside the material.

When analyzing this expression there is a minimum frequency (threshold) for which K = 0

           hf = Ф

Below this frequency the photons in the light beam do not have the energy to expel the electrons from the material.

Let's examine the answers

a) True. You agree with the above

b) False. The analysis is in terms of individual shock

c) False. The expulsion does not have to do with the number of photons but with the energy of each one

therefore the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron

After the initial experiment, students wondered how a person's weight would influence the results. They conducted a second experiment to determine if the mass of an object affected friction, assuming the types of surfaces remained constant. A spring scale was attached to a wooden block (1 kg). The block was placed on a wooden board and the spring scale was used to pull the block. The magnitude of the force required to start the block moving was recorded in the data table. The experiment was repeated using two, three, and four blocks. The data can be seen in the data table at the top of the page. What is the relationship between static friction and weight?

Answers

Answer:

The greater the weight of the person, the more static friction.

Explanation:

USATestPrep

Calculate the speed of an object that travels 75m in 15s.

Answers

11.1847 is what I got, sorry if I’m wrong

What structure is represented by the letter
C?
PLEASE HELP!!!!!
Choose 1 answer:
А
Lysosome
B
Nucleus
C
Vacuole
D
Mitochondria

Answers

It’s most definitely answer C.

Calories are a unit of energy that are reserved for heat energy but can be
directly converted to and from mechanical units of energy (Joules). How
many calories of energy are there in 500 Joules of energy?

Answers

Use photo to see the solve of your problem

HELP PLEASEE

when a person receives an electric shock from wires , is he most affected by a spark, corona, arc or humus solution?​

Answers

Answer:

Usually an eletric shock. You can be left with numbness and MAYBE problems with your eyes.

Explanation:

gravitational potential is the energy due to an object's:
a. motion
b. spring stretch or compression
c. position in a gravity field
d. chemical bonds.​

Answers

position in a gravitation field (c)

Answer:

The answer is C. position in a gravity field

Prominences and sunspots are both:


A. Jets of burning gas


B. Patches on the Sun's surface


C. Influenced by the Sun's electromagnetic field


D. Visible during an eclipse

Answers

Answer:

C. Influenced by the Sun's electromagnetic field

Explanation:

"Sunspots occur in pairs because each is one side of a loop of the Sun's magnetic field that reaches the Sun's surface. Solar prominences are the plasma loops that connect two sunspots."

Which machine do you think will last longer, the traditional battery and motor, or the free energy machine?

Answers

Answer:

it will most likely be the free energy

A 45.7 kg woman starts from rest at the bottom of a flight of stairs that has
a total height of 2.54 meters. She reaches the top of the stairs
in 5.00 seconds. How much power does she generate if she is moving at
2.63 m/s at the top of the stairs? Use g = 9.8 m/s2, and only include 3
numbers in your answer.

Answers

Answer:

The power generated by the woman is 259 W

Explanation:

Given;

mass of the woman, m = 45.7 kg

initial velocity of the woman, u = 0

total height ascended by the woman, h = 2.54 m

time of the woman's motion, t = 5.0 s

final velocity of the woman, v = 2.63 m/s

acceleration due to gravity, g =  9.8 m/s²

The potential energy of the woman due to the height she ascended;

P.E = mgh

P.E = 45.7 x 9.8 x 2.54

P.E = 1137.564 J

The kinetic energy of the woman due to her final velocity;

K.E = ¹/₂mv²

K.E = ¹/₂ x 45.7 x (2.63)²

K.E = 158.051 J

The total mechanical energy of the woman at the top of the stairs;

M.E = P.E + K.E

M.E = 1137.564 J  +  158.051 J

M.E = 1295.615 J

The power generated by the woman;

Power = Energy/time

Power = 1295.615 J / 5 s

Power = 259.123 W

Power = 259 W

What is the salt formed in the second sample reaction?

Answers

Answer:

This powder is sodium chloride. In the second reaction (sulfuric acid with copper(II) oxide) the resulting solution was blue in colour. When this solution was heated a small amount of white powder was noted.

Explanation:

i saw it on quizlet

: A small block with mass 0.130 kg is attached to a string passing through a hole in a frictionless, horizontal surface. The block is originally revolving in a circle with a radius of 0.800 m about the hole with a tangential speed of 4.00 m/s. The string is then pulled slowly from below, shortening the radius of the circle in which the block revolves. The breaking strength of the string is 30.0 N. What is the radius of the circle when the string breaks

Answers

Answer:

r = 0.0173 m = 1.73 cm

Explanation:

Here, the centripetal force of the block will be providing the required breaking tension in the string:

[tex]Tension = Centripetal Force\\T = F_c\\\\T = \frac{mv^2}{r} \\\\r = \frac{mv^2}{T}\\[/tex]

where,

r = radius = ?

m = mass of block = 0.13 kg

v = tangential spee of block = 4 m/s

T = Breaking Strength = 30 N

Therefore,

[tex]r = \frac{(0.13\ kg)(4\ m/s)^2}{30\ N}[/tex]

r = 0.0173 m = 1.73 cm

When finding the radius of the string at the point it breaks, the tangential

velocity is assumed to be constant.

The radius when the string breaks is [tex]\underline{6.9 . \overline 3 \times 10^{-3}} \ m[/tex]

Reasons:

The mass of the small block, m = 0.130 kg

Initial radius of the circle of rotation = 0.800 m

Tangential velocity, v = 4.00 m/s

The radius of the path of rotation is reduced as the string is pulled

Breaking strength of the string = 30.0 N

Required:

The radius of the circle when the string brakes

Solution:

[tex]Centripetal \ force = \dfrac{m \cdot v^2}{r}[/tex]

Where;

r = The radius of the circle of rotation

When the string brakes, w have;

Centripetal force = Breaking strength of the string = 30.0 N

Which gives;

[tex]\displaystyle r = \mathbf{\dfrac{m \cdot v^2}{Centrifugal \ force}} = \frac{0.130 \times 4^2}{30} =6.9\overline 3 \times 10^{-2}[/tex]

The radius of the circle when, the string breaks r = [tex]\underline{6.9\overline 3 \times 10^{-2}} \ m[/tex]

Learn more here:

https://brainly.com/question/20905151

A ball is rolling down a hill. Wich action would slow the ball down?

Answers

friction.............................

the ice and steam point on a thermometer are found to be 96ml apart. what temperature is recorded when the length of mercury thread is 33.6ml above the ice point

Answers

Answer:

33.6 / 96   is the fraction of the temperature between ice and freezing

33.6 / 96 = .35

So C = .35 * 100 = 35 deg C  where the ice point would be 0 deg C

You can convert C to F

F = 9 / 5 * C + 32 = 9/5 * 35 + 32 = 95 deg F

A soft drink (mostly water) flows in a pipe at a beverage plant with a mass flow rate that would fill 220 0.355 - L cans per minute. At point 2 in the pipe, the gauge pressure is 152kPa and the cross-sectional area is 8.00cm2. At point 1, 1.35m above point 2, the cross-sectional area is 2.00cm2. Part A Find the mass flow rate. M

Answers

Answer:

[tex]1.302\ \text{kg/s}[/tex]

Explanation:

[tex]\rho[/tex] = Density of water = [tex]1\ \text{kg/L}[/tex]

[tex]dV[/tex] = Change in volume = [tex]220\times 0.355\ \text{L}[/tex]

[tex]dt[/tex] = Time elapsed = 1 minute = 60 seconds

Mass flow rate is given by

[tex]\dot{m}=\rho\dfrac{dV}{dt}\\ =1\times \dfrac{220\times 0.355}{60}\\ =1.302\ \text{kg/s}[/tex]

The mass flow rate is [tex]1.302\ \text{kg/s}[/tex].

Two ice skaters, with masses of 40.0 kg and 65.0 kg , are at the center of a 50.0 m -diameter circular rink. The skaters push off against each other and glide to opposite edges of the rink. Part A If the heavier skater reaches the edge in 10.0 s , how long does the lighter skater take to reach the edge

Answers

Answer:

6.15 s

Explanation:

From the question,

Applying the law of conservation of momentum

Momentum of the Heavier skater = Momentum of the lighter skater.

Mv = mV................. Equation 1

Where M = mass of the heavier skater, m = mass of the lighter skater, v = Velocity of heavier skater, V = velocity of the lighter skater.

But,

v = r/t........................ Equation 2

V = r/t'................ Equation 3

Where r = radius of the circular rink, t = time taken for the heavier skater to reach the edge, t' = time taken for the lighter skater to reach the edge.

Substitute equation 2 and equation 3 into equation 1

M(r/t) = m(r/t')............. Equation 4

Given: M = 65 kg, m = 40 kg, r = 50/2 = 25 m, t = 10 s.

Substitute into equation 4 and solve for t'

65(25/10) = 40(25/t')

162.5 = 1000/t'

t' = 1000/162.5

t' = 6.15 seconds

Proton traveling across a capacitor A proton enters with a velocity v between the plates of a capacitor as shown in the figure. What is the direction of the magnetic field needed so that the proton continues its trajectory, undeflected? Explain each step of your reasoning.

Answers

Answer:

Please see the direction of force in the attachment

Explanation:

As the particle enters the capacitor, it experiences electric. In order to move in the same direction as the electron was moving before entering the capacitor, the force due to the electric field of capacitor must be balanced by the magnetic field.

The direction of particle is shown in the attachment.

As we know,

Force = q (v *B)

Assertion: In electrical circuits the connecting wires are usually made of thick copper wires. Reason: Thicker wires offer higher resistance and the wires are made of copper as the electrical conductivity of copper is low

a)Both A and R are true and R is the correct explanation of A.b)Both A and R are true, and R is not the correct explanation of A.c)A is true, but R is false. d)A is false, but R is true. e)Both A and R are false.

Answers

There actually three assertions here: one in A and two more in B.

All three assertions, as well as the reasoning described in this mess, are all False.

The correct choice from the list is e), but that doesn't even describe the complete Falseness of this disaster.

Question 1 of 10 Which characteristic of nuclear fission makes it hazardous?
O A. The process destroys every atomic nucleus that goes through it.
O B. The process changes existing atoms into atoms of different elements
C. The process requires very high pressures.
O D. The radioactive wastes it produces can spread to any part of the environment

Answers

Answer:

D.

The radioactive wastes it produces can spread to any part of the environment.

Explanation:

Fission is the name given to the splitting of a heavy nucleus into two medium-mass nuclei. Fission is said to be induced if it results from the absorption of a neutron to form an unstable nucleus that decays by fission. The induced fission usually produces further neutrons accompanying the fission fragments.

Answer:  D. The radioactive wastes it produces can spread to any part of the environment

Explanation:

Which is the correct formula for calculating speed?
A. speed - distance - time
B. speed = distange + time
C. speed = distance - time
D. speed = distance - acceleration

Answers

Answer:

speed=distance/time

Explanation:

its distance over time like division

Please Help!!!

For A&B

Answers

Answer:

A. 40N

B. 5m/s

Explanation:

A.

Impulse is equal to the area under the curve of a force vs. time graph. In this case, the area is in the shape of a triangle with base 8 (12-4=8) and perpendicular height 10:

Area of a triangle = (1/2)bh

A=(1/2)*8*10

=40

ANSWER: 40N

B.

Impulse = mass * velocity

40 = 8v

v = 5

ANSWER: 5m/s

An iron wire has a length of 1.50 m and a cross sectional area of 0.450 mm2. If the resistivity of iron is 10.0 ✕ 10−8 Ω · m and a potential difference of 0.800 V is maintained across its length, determine the current in the wire (in A)

Answers

Answer:

2400A

Explanation:

R=pL/A

R-Resistance

p-Resistivity=10.0 x 10^-8

L-1.5m

A-Cross sectional Area=0.00045

R=10.0 x 10^-8 x 1.5 ÷ 0.00045

and=0.000333333

I-current

V-potential difference

I=V/R

0.800÷0.000333333

Ans=2400A

1. You are given a bottle that contains 4.59 cm of a metallic solid. The total mass of the bottle
is 35.66 g. The empty bottle weighs 14.23 g. What is the density of the solid?​

Answers

26.3g hcvovvyvubbihihhijiubvuvuvyvyv
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