D&D 5E - Questions about globe of invulnerability 5e

Can it protects someone other than the caster? since it has 10 ft radius, like stepping in front of a fireball explosion to protect someone

Can an allied caster cast heal or something good trough the globle?

Can you cast from inside the globe?

Has anny effects vs arrows or other physical attacks?

Sorry if this has been asked before

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