Because the universe is sort of like the surface of a balloon just like soap bubbles. The reason for this, is because of all the clusters and superclusters that are found within the bubble walls. Hope that helps!
this is a link to a web sight with a diagram to help you
https://www.google.com/url?sa=i&source=images&cd=&ved=2ahUKEwjw4v7knNDgAhVyUN8KHWgWD-wQjRx6BAgBEAU&url=%2Furl%3Fsa%3Di%26source%3Dimages%26cd%3D%26ved%3D%26url%3Dhttps%253A%252F%252Ffuturism.com%252Fwhere-do-all-the-elements-come-from%26psig%3DAOvVaw19_FOCuWs_nMsyY1YT0Da-%26ust%3D1550955269844922&psig=AOvVaw19_FOCuWs_nMsyY1YT0Da-&ust=1550955269844922
Answer:
Periodic
Explanation:
A periodic (or repetitive) wave has continuously repeating pattern with characteristics such as amplitude, wavelength and frequency. In a periodic wave, a series of pulses that are evenly timed would be created. In other words, the wave pattern in a periodic wave repeats at regular intervals.
An example of a periodic wave is the sound from the strings of a violin.`
Answer: 5 km/hr
Explanation:
speed= distance divided by time
20/4
= 5 km/hr
Soaking up spilled milk with a paper towel
