How to show that there is no embedding or immersion of a torus into a $S^2$?

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How to use transversality for the embedding and covering spaces for immersion?

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As indicated in the comments, immersion implies that this is a local homeomorphism, and since the torus is compact, it is a covering. For coverings $X\to Y$ we have the Riemann-Hurwitz formula: $$\chi(X)=d\chi(Y),$$ where $\chi$ is the Euler characteristic, and $d\geq 1$ is the degree of the covering. Since $\chi(T)=0$ and $\chi(S)=2$, this is impossible.