I am a seven-letter word but if you remove four of my letters I will have one left. What word am I?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

The below given figure comprises of a pattern through which you can determine the missing letter. Can you push your mind to find the pattern and add the missing letter?

I go up and I go down.
I go up towards the beautiful sky and down toward the green ground.
I am present tense.
I am past tense too
Children love me.

Who Am I?

What jumps when it walks and sits when it stands?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

Can you count the number of triangles inside a triangle?

what's the probability of getting a king or a queen from a pack of 52 cards?

What number divided by 4 is the same as that number minus 4?

What is the largest number you can write with just 3 digits?