Astronomers expect the milky way to collide with the andromeda galaxy in about 3 billion years.
a. true
b. false

Yes, it is true that astronomers expect the Milky Way to collide with the Andromeda galaxy in about 3 billion years. It is more than 3 billion years, however - more like 4, but it is still inevitably going to happen. By then, our Sun is probably going to die and destoy the Earth, but we won't be alive to see it anyways, so it doesn't really matter.

29.1-12=17.1the answer is this one

Decomposition is the cycle at which bacteria breaks down any organic material into the soil