Differential Equations Questions

What is the degree of the following differential equation?
$$x=\sqrt{1+\frac{d^{2}y}{d{x}^2}}$$

What is the general solution of $(1+e^x)ydy=e^{x}dx$? (where $c$ is a constant of integration)

Rate of growth of bacteria is proportional to the number of bacteria present at time. If $x$ is the number of bacteria present at any instant $t$, then which one of the following is correct? (Let the proportional constant equal to $2$)