Bill will do none, because he is the teacher. Helena will do the math problems
Gravity's Role in Making Stars. When a clump of interstellar gas and dust is small and dense enough, gravity plays a decisive role in turning that material into a new star.
Answer:
A) Light is made up of waves.
Explanation:
Light is a form of electromagnetic waves.
Electromagnetic waves consist of electric and magnetic fields that oscillate periodically in a plane perpendicular to the direction of motion of the wave, therefore they are transverse in nature.
All electromagnetic waves travel in a vacuum at the speed of light:

Moreover, electromagnetic waves are classified into 7 different types depending on their frequency and wavelength. From lowest to highest frequency (and so, from longest to shortest wavelength), we have:
Radio waves
Microwaves
Ultraviolet
Visible light
Infrared
X-rays
Gamma rays
Visible light is part of this electromagnetic spectrum, and corresponds to the part of the electromagnetic waves that our eye is able to see. In particular, we perceive waves of different wavelength and frequency as different colors: for instance, violet/blue light corresponds to the shortest wavelength that we can see, while red light corresponds to the longest wavelength that we are able to see.
Also, for visible light wave we can describe their brightness, which corresponds to the intensity of the wave, which is a property of all waves.
So the correct answer is
A) Light is made up of waves
There are two important responsibilities that are only for U.S. citizens: to vote in federal elections and to serve on a jury. ... By voting, citizens are participating in the democratic process. Citizens vote for leaders to represent them and their ideas, and the leaders support the citizens' interests.