Can you replace the question mark with the correct number?

Can you find out the remainder when 3^300 is divided by 5?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

John is 45 years older than his son Jacob. If you find similarities between their ages, both of their ages contain prime numbers as the digits. Also, John's age is the reverse of Jacob's age.

Can you find their ages?

I have some blue and red sock in my drawer. I have a total of 4 socks. I pick 2 socks and the chance that I get a pair of red socks is 1/2.

What is the chance of picking a pair of blue socks?

I travel all around the world but always stay in the corner. What am I?

What number when divided in half becomes zero?

Replace the question mark with the correct number in the below-given picture?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You are given four results as below:
1111 = F
2222 = E
3333 = T
Then, can you find out how to code 4444?