Question

What has no hands but might knock on your door, and you better open up if it does?

Answer 1

$\huge\sf\underline{♡Answer♡}$

Ohkay....

So, What has no hands but might knock on your door, and you better open up if it does?

=> Opportunity

People who misses opportunities can never be successful in life, so if opportunity comes to you, You better open up if it comes at the right time.

Answer 2

$\bf{Answer :-}$

Opportunity

$\bf{Explanation :-}$

Opportunity is a lucky chance or good time where it makes a thing feasible or possible to do something.

Opportunity is an abstract Noun so it is obvisous that it doesn't have any hands.

Opportunity knocks the door is an idiom. It means the time when someone gets a chance to accomplish what they want.

As it allows us to complete our aim, we should open the door when opportunity knocks. If we don't open it, we would miss our way towards success

Thus, we can conclude that, Opportunity is a thing which doesn't have hands but knocks the door, and it is better when we open the door after the knock.

Therefore the answer is - $\bf{OPPORTUNITY}$