Solution:

19.

The numbers are marked in the picture below,

Solution:

Chicken-8

Explanation:
Let's start with distinct features

Chicken-2 has an extra toe.
Chicken-3 has fewer tail feathers.
Chicken-5 has only one thigh crease.
Chicken-6 has an extra feather around the neck.
Chicken-7 is looking up.
Chicken-8 has a longer butt crease.

But this riddle is not about the features. The different chicken is 8 as cannot be seen by any chicken.

Solution:

The first door.

The bear will try to protect the cub, even if you offer her your food.
Swimming a lake with crocodiles is definitely not a good idea.
You can use your bucket to fight the fire with the water from the lake and can also distract the crocodiles with the food you had.

Solution:

38

Solution:

A

The ladder of B is about to break.

Solution:

Line - C

Explanation:
A^2= 3^2 + 6^2 => 9+36 => 45
B^2= 5^2 + 5^2 => 25+25 => 50
C^2= 6^2 + 4^2 => 36+16 => 52
D^2= 7^2 + 1^2 => 49+ 1 => 50

Solution:

What.

It is clearly mentioned that "What is the name of the fourth son". Note it's a statement with a period(.) and not with a question mark(?).

Most of the people has given the answer as "East" or "Someone".

Solution:

The Girl

Solution:

Ground Floor.

Any person staying on the floor other than the ground floor would have to call the elevator to reach their respective floors. So, the ground floor calls the elevator way above the individual floors.

Solution:

The kids have 4 slices of pizza in their hands but only three pieces are missing from the pizza box.