Hy tikki! I've asked some questions, so of you find the questions as easy, then answer it. I'll surely mark you as brainliest :)
Answer:
Voltage-gated calcium ion channels open, and calcium ions diffuse into the cell
Answer:

Work done to bring three electrons from a great distance apart to 3.0×10−10 m from one another (at the corners of an equilateral triangle) is 
Explanation:
The potential energy is given by:
U=Q*V
where:
Q is the charge
V is the potential difference
Potential Difference=V=
So,

Where:
k is Coulomb Constant=
q is the charge on electron=
r is the distance=
For 3 Electrons Potential Energy or work Done is:


Work done to bring three electrons from a great distance apart to 3.0×10−10 m from one another (at the corners of an equilateral triangle) is 
Answer:
The frog's horizontal velocity is 0.2 m/s.
Explanation:
To solve this problem, we must first remember what velocity is and how we solve for it. Velocity can be solved for using the formula x/t, where x represents horizontal distance and t represents time (in seconds), that it takes to travel this distance. If we plug in the given numbers for these variables and solve, we get the following:
v = x/t
v = 0.8m/4s
v = 0.2 m/s
Therefore, the correct answer is 0.2 m/s. We can verify that these units are correct because the formula calls for distance divided by time, so meters per second is a sensible answer.
Hope this helps!
From our perspective on Earth, two types of eclipses <span>occur: </span>lunar<span>, the blocking of the </span>Moon<span> by Earth's shadow, and </span>solar, the obstruction of the Sun by the Moon<span>. ... When Earth passes directly </span>between<span> Sun and </span>Moon<span>, its shadow creates a </span>lunar eclipse<span>.</span>