27. in the 1830s, inventions such as the mech
cut cleanly through sod allowed settlers in the
a. run their farms profitably without relyir
b. buy additional land from the federal go
c. clear land and harvest more grain with
d. establish east-to-west trails to reach ti

In the 1830s, inventions such as the mech  cut cleanly through sod allowed settlers in the Clear land and harvest with more grain.

Explanation:

radioactive dating, also known as  radioisotope dating  is a process that in  estimating the approximate  age  of  rocks. these data can be analyzed from  the studies dealing with the  decay of the radioactive elements that are present in these rocks. in nature, there are a few types of materials or atoms which are quite unstable and they spontaneously decay or breakdown to form other kinds of atoms.

i think it was   tsar alexander ii