Valence electrons are the electrons in the outermost energy level of an atom — in the energy level that is farthest away from the nucleus.
I think it's A.
Answer:

Explanation:
According to the free-body diagram of the system, we have:

So, we can solve for T from (1):

Replacing (3) in (2):

The electric force (
) is given by the Coulomb's law. Recall that the charge q is the same in both spheres:

According to pythagoras theorem, the distance of separation (r) of the spheres are given by:

Finally, we replace (5) in (4) and solving for q:

The car travels at a speed of 25m/s.
<u>Explanation:</u>
Given-
Mass, m = 1500kg
Coefficient of friction, μk = 0.47
Distance, x = 68m
Speed, s = ?
We know,

and
F = μ X m X g
Therefore,
μ * m * g = m * a
μ * g = a
Let, g = 9.8m/s²
So,


We know,

where, v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
If the car comes to rest, the final velocity, v becomes 0.
So,

The car travels at a speed of 25m/s.
Answer:
The level of seed in each feeder
Explanation:
The independent variable is the variable which is the suspected cause of an observation, it is the variable that produce the effect observed in the dependent variable. The dependent variable is the variable that is measured
The independent variable is normally the x-value while the dependent variable is the y-value
In the question, Lana wants to find out the kind of birdseed that the neighborhood birds like (to eat) the most by feeding them different types of birdseed and measuring the level of the birdseed in the feeders at regular intervals
the independent variable is the bird seed types which Lana gives to the birds, to determine the type of bird seeds the birds like
The dependent variable is the level of the seed in the feeder which depends on the type of seeds the birds like.
The natural factor that is most likely to support the formation of an oceanic island is the rise of magma from the seafloor. Oceanic islands are also otherwise known as volcanic islands. When volcanoes erupt, they create layers of lava that break the surface of the water. When the tops of the volcanoes emerge, an island is created.<span> </span>