Solution:

Murder.

Explanation:
1. There are signs of the struggle in the room as the clock is broken.

2. Two water glasses in the room indicate the presence of two people which also suggest that the killer is known to the victim.

3. There are a book and a pen on the bed which indicates that the dead person was reading and a suicide note was written from another pen which seems to be planted.

4. The man crutches are too far from the man.

Solution:

Either Rain Cloud Or Air

Explanation
=== Rain Cloud ===
I don't have a mouth but can roar - Thunder
I don't have eyes but can cry - Rain
I am really good - Rain is good
but bad sometimes - Storms
Without me, all will die - rain is the necessity for agriculture and human being

=== Air ===
I don't have a mouth but can roar - Wind
I don't have eyes but can cry - Moisture
I am really good - Rain is good
but bad sometimes - Hurricanes
Without me, all will die - Oxygen

Solution:

The white chip is circled.

Solution:

I Over Ate

Explanation:
Check the mathematical solution on the image below.
Also, 8 in 2018 resembles a fat person.

Solution:

The cowboy can fit the horses as shown below.

[T] [E] [N] [H] [O] [R] [S] [E] [S]

Solution:

Pour 3 lumps on cup-1 and cup-3 and 4lumps on cup4 and place them as shown in the picture.

Explanation:
Now,
Cup-1 got three sugar lumps
Cup-3 got three sugar lumps
Cup-2 got three seven lumps (3 of cup-1 and 4 of its own)

Solution:

Two right foot :-)

Solution:

8m

Explanation:
From green bar, it's clear that
the height of vertical bar = 2/3 of uninterrupted shadow length

Therefore shadow of 6m of red bar indicates the height of 4m.
The remaining red bar casts a direct 1:1 vertical projection on the wall.

Therefore total length = 4m + 4m = 8m.

Solution:

The hidden cat is circled below.

Solution:

40

Explanation:
A) 123 + 0 = 16
20 - (1+3)

B) 234 + 0 = 24
30 - (2+4)

C) 345 + 0 = 32
40 - (3+5)

Then
456 + 0 = 40
50 - (4+6)