Plasmolysis is the reason. The reason that the Elodea cell prevents from collapsing completely is that the Plasmolysis is the main reason because it always has water to keep it full. The answer in this question is Plasmolysis is the reason because it always has water to keep it full.
The double membrane. It's theorized that chloroplasts used to be their own single-celled organism in the environment (and therefore with its own membrane). Then, the theory states, a larger cell took in the chloroplast by endocytosis, which involves surrounding the chloroplast in the large cell's own membrane. The chloroplast would then have two membranes surrounding it. This is similar to the thinking for mitochondria becoming an organelle as well. Hope this helps! :)
Answer:
Wrinkled peas need to have genotype rr, since the wrinkled trait (r) is recessive