1790sCradle and scythe introduced; invention of cotton gin (1793); Thomas Jefferson's plow with moldboard of least resistance tested (1794)
1793Eli Whitney invents the cotton gin, which contributes to the success of cotton as a Southern cash crop
1797Charles Newbold patents first cast-iron plow
1800
1801Thomas Moore of Maryland invents the icebox refrigerator
1819Jethro Wood patents iron plow with interchangeable parts
Answer:
unitary systems, federal systems, and confederate systems.
Explanation:
Answer:
the senate has 100 members
Explanation:
they have to have 100 members of at least 30 years of age
