<span>This variation be justified by:
</span>Migration to an environment different from their birthplace, and adaptation to the available food, ultimately leading to speciation. because <span>birds use their beaks to eat.</span>.
Chloroplasts convert sunlight (energy) with water and carbon dioxide gas to produce sugar (food) for plants and some types of alge. They do this process with chlorophyll and the process itself is called photosynthesis. In a good number of plants this process has two systems the photosystem I and photosystem II.
Nobody can answer since it was spoken about in your class, sorry :)
<span>Mucous membranes provide a mechanical barrier at body openings. They also line the respiratory, GI, urinary, and reproductive tracts. Mucous membranes secrete mucus, a slimy substance that traps pathogens. The membranes also have hair-like cilia.</span>
