Animal Riddlebees

See if you can solve these riddlebees:

My first is in bean but not in pea;
My second you find in coffee and tea;
My third is in both shell and sea.
Who am I?

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bee

My first is in both grass and grow;
My second you see in learn and know;
My third is there inside the dough.
Who am I?

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gnu

My first's at the end of every song;
My second is in both short and long;
My third you find in ways and means;
My fourth is in slants but not in leans.
Who am I?

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goat