Gregor was forced to work from a young age. He became a friar and lived at an abbey.
He was sent to the University of Vienna, and when he returned he taught science. However, he always wanted to do more.
He designed an experiment using pea plants to look at how parents give their kids genes for traits. His hypothesis was that dominant and recessive genes exist in pairs.
Mendel wanted to observe and record the outcome of hybrid pea plants. He cross-bred by hand pollinating each plant, and observed which peas were yellow and which were green. As well as other traits.
Although his discovery was great, and contributed to science greatly now, then they didn't understand its importance. His papers were published, but they were overlooked. He died at 61 without much recognition for his scientific discovery.
Now we have Mendel's Laws. These help us understand dominant and recessive genes, and how chromosomes are paired, and separated. Now we understand how our DNA codes for our genes and traits, and how it's inherited from out parents.