I need help with the following questions:

I have been given the production function: f(l,k)=(l²+k²)^1/3

1) I have to explain if the production function has decreasing, increasing or constant return to scale?

how do I explain this?

2) Is the production function concave ?

3) is the marginal product for input 1 and input 2 decreasing?

4) how do I calculate TRS from this production function?

and finally 5) does the production function decreasing numeric TRS along the isoquant line?

thank you!