If you stand up in a big room and echo, your voice will echo
from the walls. As long as the room is empty. Since
the speed of sound is constant, depending on air density, the more humid the
air the faster and farther sound travels. The
speed of sound is constant, you could measure the time it takes for your voice
to echo off the walls. The same thing happens with Doppler radar, but it’s not voice,
it has higher frequency signals.<span> </span>
Answer:
1.38*10^18 kg
Explanation:
According to the Newton's law of universal gravitation:

where:
G= Gravitational constant (6.674×10−11 N · (m/kg)2)
ma= mass of the astronaut
mp= mass of the planet

so:

The answer to that would be A. the national organ transplant Act of 1984 the goals of the OPTN are to increase the number of and access to transplants, improve survival rates after transplantation, and to promote patient safety and efficient management of the system.
Reactions occur when two or more molecules interact and the molecules change. Bonds between atoms are broken and created to form new molecules. That's it.
I think it was by boat and coming from over seas