Researchers have found that the larvae of all North American firefly species glow as a warning sign to ward off predators. However, the presence and use of lighting organs in adult fireflies vary greatly. Some species use glowing or light flashes as mating signals, while other species produce pheromones as mating signals and do not glow at all. Discuss how the physical characteristics and mating behavior of North American fireflies support the theory of speciation. In your discussion, provide a hypothesis to explain the driving force behind the differences in mating signals among the species.

Answer:

(AIDS) is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus (HIV). By damaging your immune system, HIV interferes with your body's ability to fight infection and disease. HIV is a sexually transmitted infection (STI). It can also be spread by contact with infected blood or from mother to child during pregnancy, childbirth or breast-feeding.

Explanation:

To help prevent the spread of HIV: 1. Use treatment as prevention (TasP). If you're living with HIV, taking HIV medication can keep your partner from becoming infected with the virus.

Answer:

50 out of 100 (ik its right)

Answer:

57? 17? 7? 77? 37? 47? 87? 97? 27? 67?

Explanation:

id'k

Explanation:

Given that,

A girl pushes her little brother on his sled with a force of 200. N for 850. m

We need to find the work done by the force of friction acting on the sled. The force of friction is 200 N

Net force = 200 N - 200 N = 0

Work done = 0

If force of friction is 300 N.

Net force = 300 N - 200 N = 100 N

The work done by a force is given by :

W = Fd

Put values,

W = 100 × 850

W = 85000 J

Hence, this is the required solution.

Question:

Find the magnitude and direction of the electric field at points that are at the following distances from the center of the aluminum rod:

(a) 0.5 cm, (b) 1.5 cm, (c) 2.5 cm, (d) 3.5 cm, (e) 7.0 cm

Answer:

(a) 0

(b) 4.795 N/C

(c) 2.877 N/C

(d) 2.055 N/C

(e) 1.027 N/C

Explanation:

The given parameters are;

The inner radius of the copper = 2 cm

The outer radius of the copper - 3 cm

The radius of the aluminum rod, r = 1 cm

The radius of the aluminum rod = 4 pC/m

a) The charge at the 0.5 cm from the center of the aluminum rod, E = 0

There is no charge inside the rod given that the aluminum road is a conductor of electricity, having all the charge on its surface

b) At 1.5 cm, we have;

[tex]E = \dfrac{2 \cdot \lambda}{4 \cdot \pi \cdot r \cdot \epsilon_0}[/tex]

Where;

[tex]\dfrac{ \lambda}{4 \cdot \pi \cdot \epsilon_0} = 8.99 \times 10^9 \times 4 \times 10^{-12}[/tex]

r = 1.5 cm = 0.015 m

∴ E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.015 ≈ 4.795

The magnitude of the electric field, E = 4.795 N/C

The direction of the charge depends on the charge sign on the rod

c) At 2.5 cm, we have;

r = 2.5 cm = 0.025 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.025 ≈ 2.877

The magnitude of the electric field, E ≈ 2.877 N/C

d) At r = 3.5 cm, we have;

r = 3.5 cm =  0.035 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.035 ≈ 2.055

The magnitude of the electric field, E ≈ 2.055 N/C

e) At

r = 7.0 cm = 0.070 m

E = (2 × 8.99 × 10⁹ × 4 × 10⁻¹²)/0.07 ≈ 1.027

The magnitude of the electric field, E ≈ 1.027 N/C

Answer:

what

Explanation:

Answer:

El periodo del péndulo simple, para oscilaciones de poca amplitud, viene determinado por la longitud del mismo y la gravedad.

Explanation:

No influye la masa del cuerpo que oscila ni la amplitud de la oscilación. Donde: T: Periodo del péndulo.

Answer:

Proton

Explanation:

Atomic number, the number of a chemical element in the periodic system, whereby the elements are arranged in order of increasing number of protons in the nucleus. Accordingly, the number of protons, which is always equal to the number of electrons in the neutral atom, is also the atomic number.

Answer:

hope this will help

please give brainliest if correct

Answer:

-1.715J

Explanation:

B: (9.8)(0.7kg)(0.25m)=1.715J

A: (9.8)(0.7kg)(0)=0J

Answer:

How is a water rocket different than a compressed air rocket?

Usually the rocket is made from a 2-liter soda pop bottle. Before launch, the bottle is filled with some amount of water, which acts as the "propellant" for the launch. Since water is about 100 times heavier than air, the expelled water produces more thrust than compressed air alone.

Answer:

true Mid-ocean ridges are sites where old crust sinks into the asthenosphere.

Explanation:

hope it helps

Answer:

(a) η = 0.1742 = 17.42 %

(b) W = 31.64 W

(c) m = 0.58 kg

Explanation:

(a)

The efficiency of a Carnot's engine is given as follows:

[tex]\eta = 1-\frac{T_2}{T_1}[/tex]

where,

η = efficiency = ?

T₁ = source temperature = 100°C + 273 = 373 K

T₂ = sink temperature = 35°C + 273 = 308 K

Therefore,

[tex]\eta = 1 - \frac{308\ k}{373\ k} \\[/tex]

η = 0.1742 = 17.42 %

(b)

Another formula for the efficiency of Carnot's Engine is:

[tex]\eta = 1 - \frac{Q_2}{Q_1}[/tex]

where,

Q₁ = Input heat rate

Q₂ = Heat rejected = 150 W

Therefore,

[tex]0.1742 = 1 - \frac{150\ W}{Q_1}\\\\ \frac{150\ W}{Q_1} = 1-0.1742\\\\Q_1 = \frac{150\ W}{0.8258}[/tex]

Q₁ = 181.64 W

Now, for the useful power output:

[tex]W = Q_1-Q_2\\W = 181.64\ W - 150\ W\\W = 31.64\ W[/tex]

where,

W = Useful Output

W = 31.64 W

(c)

The heat required to condense steam i given as:

[tex]Q = mH\\Q_1t=mH\\m = \frac{Q_1t}{H}[/tex]

where,

m = mass of steam condensed = ?

t = time = 2 h = 7200 s

H = Latent heat of condensation of steam = 2260 KJ/kg = 2260000 J/kg

Therefore,

[tex]m = \frac{(181.64\ W)(7200\ s)}{(2260000\ J/kg)}[/tex]

m = 0.58 kg

Answer:

b

Explanation:

because a quark have many kinds of flavor

Answer:

[tex]\Large \text{A}[/tex]

Explanation:

Flavor is the name given by scientists which refers to the type of quark.

Answer:

v_f = -7.5 m / s

Explanation:

Let's analyze this exercise a little, two forces that act on a body for different time intervals are indicated, each force creates an impulse and since this is a vector quantity we must add in the form of vectors. The net momentum is

we assume that the direction to the right is positive

             I = I₁ + I₂

             I = F₁ Δt₁ - F₂ Δt₂

             I = 3  1.5 - 4  3

             I = -7.5   N s

now let's use the relationship between momentum and momentum, suppose the object starts from rest (vo = 0)

             I = Δp

             I = m (v_f - v₀)

             v_f = I / m

              v_f = -7.5 / m

to finish the calculation we must assume a mass m = 1 kg

              v_f = -7.5 m / s

the negative sign in the body is moving to the left

Answer:

As the temperature is increased the more the energy store

Answer:

Strategies to ensure that - forests are continued source of resources.

Explanation:

Forests continued sustainable use, ie today's use without compromising with tomorrow's needs - can be done using following strategies

Answer:

i don't know but have a good day

Answer:

Halos, blurriness, and night blindness causes night vision (symptoms) while vitamin-A,corrective lenses, such as eyeglasses or contacts, can improve or help night vision.

Explanation:

I bet you will get full Marks if you write it!!

(please note that you will have to mark me as brainliest if it helped you)£

Answer:

conductor

Does not easily transfer electricity

Explanation:

mass of earth (m1)=5.97×10^24

mass of moon (m2)=7.35×10^22

distance between their center (d)= 3.84×10^8

G=6.67×10^-11

now,

gravitational force =(F)= G(m1×m2)/d²

Answer:

Efficiency = 10.2 %

Explanation:

Given the following data;

Mass = 70 kg

Height = 50 m

Velocity = 10 m/s

We know that acceleration due to gravity is equal to 9.8 m/s².

To find the efficiency of energy conversion from potential to kinetic;

First of all, we would determine the potential energy;

P.E = mgh

P.E = 70 * 9.8 * 50

P.E = 34300 J

For the kinetic energy;

K.E = ½mv²

K.E = ½ * 70 * 10²

K.E = 35 * 100

K.E = 3500

Therefore, Input energy, I = 34300 J

Output energy, O = 3500 J

Next, we find the efficiency;

Efficiency = O/I * 100

Substituting into the formula, we have;

Efficiency = 3500/34300 * 100

Efficiency = 0.1020 * 100

Efficiency = 10.2 %

c tell your parents it could be someone very dangerous and meeting people online can be very risky I would also tell my bsf just for fun tho

Answer:

:c: H* : A: :C: H* :A: :C: H* :A:

Answer:

v_t = [tex]\frac{2 g \ ( \rho_b - \rho_l ) r^2 }{9 \ \eta }[/tex]

Explanation:

Let's describe the motion and forces on the marble when it falls into the graduated cylinder filled with water.

Initially, the marble in the air falls under the influence of its weight (gravity force), when it enters the water, a friction force appears that INCREASES with SPEED and opposes the movement, this force is called Stokes force.

              Fr = 6π R η v

where η is the viscosity of water

also because of this in a liquid it has an upward thrust, given by Archimedes' law, this thrust is CONSTANT

              B = ρ_l g V_l

in that case the volume of liquid(V_l)  is equal to the volume of the marble.

Constant force of gravity

               W = mg

using the concept of density

                ρ_body = m / V

                W = ρ_body g V_body

we apply Newton's second law

                Fr + B - W = ma

the friction force increases and the other two are constant, so acceleration decreases until reaching zero, at this point the forces are in BALANCE

                Fr + B - W = 0

and the speed remains constant, being called TERMINAL SPEED

                v_t = [tex]\frac{2 g \ ( \rho_b - \rho_l ) r^2 }{9 \ \eta }[/tex]

from this point on, the displacement is proportional to the time

Answer:

Here it is lol

Explanation:

Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have 'drifted' across the ocean bed. The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his assumption that the continental landmasses were drifting across the planet, sometimes plowing through oceans and into each other. He called this movement Continental drift. Many people did not believe the theory and he received criticism for it because it was incomplete and flawed, and he could not fully explain what drove the continental drift to occur. You can best see this in the quote by Geologist R. Thomas Chamberlain. “If we are to believe in Wegener’s hypothesis we must forget everything which has been learned in the past 70 years and start all over again.”The idea of Continental drift includes the theory of plate tectonics, which explains the cause of the continents drifting. The earth’s outer shell composed of plates moves a little bit every year. The heat coming from the interior of the earth triggers this movement to occur through convection currents inside the mantle. And that all of the Earth's continents were once part of an enormous, single landmass called Pangaea.

As part of his hypothesis of a mega continent, he discovered research papers on fossils supporting his theory that Africa and South America had once been connected. These studies indicated evidence of fossils of identical land animals that had lived in both areas simultaneously hundreds of millions of years ago. One fossilized land organism that added credibility to Wegener’s theory was that of the Mesosaurus, a small, freshwater aquatic reptile from the Permian period about 260 million years ago in what is now Easternsouth America and Southwestern Africa. Wegener asserted that South America and Africa must have been joined during that period of history because fossils of Mesosaurus are limited to those regions, and if Mesosaurus had been able to make the long journey across the South Atlantic, its fossils would likely be more widely distributed.

Answer:

C

Explanation:

Without thinking, the answer is C.

The problem is with D. Of course it is going to depend on the transparency. If the material is a rock, then the light won't go through, and n >>>1.  I don't think you are intended to think that way, but I sure wish D wasn't there. I'd answer C, but be prepared to see it come out as D.

Answer:

it and i quote you "is less than in free space

Explanation:

i cant explain

Answer:

a.  Generator

Explanation:

Answer:

A

Explanation:

A battery derives its energy chemically. D is not the answer.

C develops its energy by burning fuel and transferring the heat energy to make water into steam which is chemical/mechanical. Not C

B A Tesla Coil produces a very high voltage and a low current. Not B.

The answer left is A. It converts mechanical energy into electrical energy. It is the only device listed that does this.

Answer:

Either orally or rectally

Explanation:

(I didn't visit the vet clinic, I just searched it up)

It depends on the animal. You can't check a birds temperature with a thermometer because it will rupture its cloaca gland but you can check its poop.

Answer:

thermometer is used by veterinary doctors to find out the temperature of domestic animals .