My aim is to carry out a generalized linear model (glm) with 1 response variable and 13 explanatory variables.Unfortunately 3 out of the 10 explanatory variables contain NA values (2/3 of data set of this 3 variables are NA values - in total 410 observations). I realized that the "step" function does not work with NA values (Why does the number of rows change during AIC in R? How to ensure that this doesn't happen?). Therfore my question: How can I proceed to automatically improve my glm without eliminating my sites with NA values?
Example (only 3 explanatory variables and 5 observations)