I Live in Water

I am the second planet from the sun.

I spin the opposite direction as Earth.

who am I?

 I have branches, but no fruit, trunk or leaves.

What am I?

I have 4 corners. I have 4 sides.

All of my sides are the same length.

Who I am?

I am the nearest planet to the sun.

I am the smallest planet in the solar system.

Who am I?

Can you name the four days of the week that begin with letter "T"