This is a promising essay.
From what I understand you need to write an argumentative text for the given statement.
What I usually do in these situations, is to identify at least two or three reasons to support my claim.
This is a matter of taste, though very useful for standardized tests like TOEFL, SAT, GRE...
Below I have made some comments about the content.
The 20th century inventions in technology, science, medicine and many other sectors
has transformed our lives
[...] have [...]
Big inventions such
An= formal easy usually doesn't have questions. Try to rephrase it as "The main reasons that small inventions..."
a baby stroller is
crucial in my life than a jet plane
"than" demands comparison. You could simply say... "a baby stroller is more important to me than a jet plane"
It makes sense!
These type of phrases don't belong in a formal essay. You could simply dismiss it.
meaningful or hopeless
More suitable antonyms for "meaningful" would be "meaningless" or "insignificant"
I recommend this website for synonyms / antonyms: thesaurus.com
Keep up the good work!