We know the fact that $K_0(-)$ and $K_1(-)$ are continuous under inductive sequence of $C^*$-algebras (in fact inductive system), i.e. $K_0(\lim_{\rightarrow} A_n)=\lim_{\rightarrow} K_0(A_n)$ similar for $K_1(-)$. In fact it is also true that $M_k(\lim_{\rightarrow} A_n)=\lim_{\rightarrow} M_k(A_n)$ for $k\in \mathbb N$.

Q1: $\widetilde{\lim_{\rightarrow} A_n})=\lim_{\rightarrow}\tilde{(A_n)}$? In fact this is a claim in someones' book, but without a proof. If we let $(X,\lambda_n)$ be the inductive limit of $A_1^\thilde\rightarrow A_2^~\cdots$, then by universal property we get a unique morphism $\lambda: X\rightarrow A^~$. How can we show $\lambda$ is injective? NB morphisms need not be unital, even though $C^*$-algebras are unital.

Q2: Can we find any other continuous functors? what about the universal group $C^*$-algebras, tensor product of $C^*$-algebras, cross product of $C^*$-algebras and so on?

Q3: Do we know some functors which is not continuous?