Let $X$ be a rationally connected smooth projective variety defined over $\mathbb C$. 


(1) Can we find a surface $S \subset X$ such that $ (-K\_X)^2 \cdot S > 0 ? $
If yes, can we assume that $S$ intersects properly a given codimension $2$ subvariety $V \subset X$ only at isolated points ? The answer is obviously **no**, as Artie pointed
out in the comments. 


(2) Can the square of the first Chern Class of $K\_X$ be numerically equivalent to $\sum \lambda\_i Y\_i$ where $\lambda\_i \in \mathbb Q\_{<0}$ are negative rational numbers, and $Y\_i$ are irreducible codimension two cycles ? 




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**Edit** : As Artie and Francesco noted, (1) is too much to ask for. I still would like
to know if (2) can hold ?


**Edit 2** : The answer to (2) is yes. If we blow up a point in Francesco's example then
we obtain a $3$-fold $Y$ with $K\_Y = -F + 2E$. Thus $K\_Y^2$ is numerically equivalent to 
$-4 \ell$, where $\ell$ is a line inside the exceptional divisor $E$.



Positivity of the anticanonical bundle of a rationally connected manifold 
It seems to me that the answer to your question is **no**, because of the following example (which came to my mind after reading Artie Prendergast-Smith's comment).


Consider a pencil $\lambda Q\_1 + \mu Q\_2$ of quartic surfaces in $\mathbb{P}^3$, and let $Z$ be its base locus, that in general will be a smooth curve of degree $16$. Blowing-up $Z$, we obtain a smooth rationally connected $3$-fold $X$ together with a map $\pi \colon X \to \mathbb{P}^1$, which gives to $X$ the structure of a fibration in $K3$ surfaces. If $F$ is the class of a fibre of $\pi$, the formula for the canonical class of a blow-up yields 


$K\_X=-F$. 


So for every surface $S \subset X$ one has $(-K\_X)^2 \cdot S=0$. 


This can be obviously generalized in any dimension, by considering a pencil of hypersurfaces of degree $n+1$ in $\mathbb{P}^n$ and blowing-up the corresponding base locus. In this way one obtain a smooth rationally connected $n$-fold $X$ with a fibration $\pi \colon X \to \mathbb{P}^1$ in Calabi-Yau varieties, and the anticanonical divisor of $X$ coincides with a fibre of $\pi$.


