Question

Sleeping just one hour less a night can prevent you from learning or functioning normally.

Answer 1

Yes, it's true you cannot learn to function normally with one or two fewer hours of sleep a night that you need.
When a person sleeps the brain starts to rest, and if you sleep for one hour your brain won't be able to function correctly when you wake up to do normal day life routine. So my answer is yes.
Hope this helps!!

Answer 2

This statement is very
$\boxed {\bf True}$


$\bf Explanation:$
Sleep holds a huge role in your health, from repairing blood vessels to synthesizing hormones sleep is an essential part of human's daily life. Research has shown us that people who sleep more frequently are able to grow muscle, synthesize hormones, repair tissue, repair blood vessels, and many more things. Lack of sleep can cause anxiety, obesity, high blood pressure, diabetes, and other chronic illnesses. 

Hope this helps!