Questions about matrices, data frames and lists

Hi ! I have troubles answering those questions coming from a random generated R questions website... Could someone please help me ? Thanks a lot

1. Create a 56 x 56 diagonal matrix C with elements 1, 2, ..., 8, 1, 2, ..., 8,...
is this correct : ```diag(1:8, nrow=56, ncol=56)```?

2. Create two integer vectors y and z where y ranges from -14 to 15 and z ranges from 9 to 38. Then merge them into a data frame and assign the result to df.
is this correct : ```y<- -14:15 z <- 9:38 df <- data.frame(y, z)```

3. Consider a hypothetical data frame obs with columns 'sun', 'weather' and 'airplane'. Write code to access the 7th row of the data frame, but excluding column 3.
I did ```obs <- setNames(data.frame(matrix(ncol = 3, nrow = 0)), c("sun", "weather", "airplane"))``` but how do you continue ?

4. Imagine a list input with six integer vectors. Write an R statement that adds 6 to every element of the 6th vector in input and outputs the resulting vector.

5. Provide code to extract the 7. element of the 1. vector of a hypothetical list list.

6. Consider a hypothetial list index containing many vectors. Provide code to extract a list containing only vectors 2 and 4 of index.