what does the below rebus means?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

How many pluses should we put between the digits of 987654321 to get a total of 99, and where?

What type of tree can I carry in my hand?

Solve the counting riddle by identifying the number of triangles in the given picture.

Find the next number in the sequence

1, 2, 6, 21, 88, __?

I hide my treasure in the ground, my tail is big and fluffy. If you spot me in a tree, please don’t call me scruffy. What am I?

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?