A. metallic
I gotta use 20 characters so ignore this bucko
Answer;
- DNA
-Some additional proof of the endosymbiotic theory includes the similarity in DNA between bacteria and mitochondria and cyanobacteria and chloroplasts.
Explanation;
-According to the endosymbiotic theory; mitochondria and chloroplasts contain their own circular DNA, similar to DNA in Bacteria, Both mitochondria and chloroplasts are surrounded by two membranes: inner and outer membrane, mitochondria are about the same size as bacteria and also mitochondria appear to have been derived from purple bacteria and chloroplasts derived from photosynthetic bacteria.
Stress can cause a virus to switch from the lysogenic cycle to the lytic cycle.
Answer:
So they are lighter and move quicker.
Explanation:
With the small wings and bodies birds have it would be hard for them to escape predators and lift their own weights if their bones were dense like humans' bones. The hollow part of the birds' bone is connected to their lungs so they have enough oxygen to fly easily. Hope this can help you! :)