Hi.
I´m begginer on R.
Have to calculate the body mass in g for the Adelie Penguins species.
I need some help how to write a code to summarize() and mean() functions to find the mean value for the variable (body_mass_g) on penguins dataset.

The online book R for Data Science (https://r4ds.had.co.nz) by Hadley Wickham and Garret Grolemund is an excellent way to learn R. For this particular problem, I suggest you look at section 5.6.