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! :)
The evaluation of their DNA and short tandem repeats will let them know if the birds are related or not. The genetic linkage will provide information about their common ancestry as well as if they belong to the same species, or are closely related species.
Answer:
Like DNA, RNA polymers are make up of chains of nucleotides *. These nucleotides have three parts: 1) a five carbon ribose sugar, 2) a phosphate molecule and 3) one of four nitrogenous bases: adenine, guanine, cytosine or uracil.
Explanation:
ribose + phosphate group + uracil