I can't do pull-ups but I could do any other excercise in a crazy level, why is this?

[_johnflin_]

I can't do pull-ups, but I could do about 300 pushups in a row, 5 sets or 45 pounds dumbells about 30 reps, plank for about 15mins straight or 30 mins, abs workout I could do like hell. I could do 50kg bicep curls about 50 reps (3sets). but I could never do pull-ups, not even one
. Why is this please help me

Updates:

[purplepoppy]

People with long arms find pullups harder. Also you could just be too heavy.

[ManWithThePlan123]

So this is just to show off... I see.