The answer is D I took the test
It’s either snow or rain if it’s a riddle sort of.
Answer:
A and B
Explanation:
The relation between frequency and wavelength is shown below as:

c is the speed of light having value 
Thus, the product of the wavelength and the frequency is constant and equal to 
<u>Option A is correct.</u>
Given, Frequency = 
Thus, Wavelength is:



Also, 1 m =
Å
So,
<u>Wavelength = 3.0 Å</u>
<u>Option B is correct.</u>
As stated above, the speed of electromagnetic radiation is constant. Hence, each radiation of the spectrum travels with same speed.
<u>Option C is incorrect.</u>
According to a periodic table, Krypton was created during the fission of Uranium.
<h3>What is the atomic number?</h3>
<em>Atomic</em> number is a characteristic associated with an element and indicates its number of protons, when a fision occurs, the total number protons is conserved.
Thus, the fission of uranium is led by two elements with <em>atomic</em> numbers 56 and 36. According to a periodic table, those <em>atomic</em> numbers are associated to elements Barium (Ba) and Krypton (Kr), respectively.
According to a periodic table, Krypton was created during the fission of Uranium. 
To learn more on fission, we kindly invite to check this verified question: brainly.com/question/6572079
Answer:
Use of telemetry and radar astronomy
Explanation:
An astronomical Unit (AU) is a unit of measuring distances in outer space, which is based on the approximate distance between the earth and the Sun.
After several years of trying to approximate the distance between the Sun and the Earth using several methods based on geometry and some other calculations, advancements in technology made available the presence of special motoring equipment, which can be placed in outer space to remotely monitor and measure the position of the sun.
The use of direct radar measurements to the sun (radar astronomy) have also made the determination of the AU more accurate.
A standard radar pulse of known speed is sent to the Sun, and the time with which it takes to return is measured, once this is recorded, the distance between the Earth and the Sun can be calculated using
distance = speed X time.
However, most of these means have to be corrected for parallax errors