The piece of evidence that charles darwin was missing when he developed the theory of natural selection was that

(a) only particular traits could be acted upon by natural selection.
(b) natural selection is referred to as the genetics
(c) the traits acted upon by natural selection were genes.
(d) traits would be inherited to an organisms offspring.

       The right answer to this question is option C. the traits acted upon natural selection were genes.

       At the time Charles Darwin developed the evolution theory, there wasn't a single study about genes in all science scenery, that could be explained by the lack of technology to study them and even to know they existed in the first place.

        So, his theory was basically talking about adaptation, if an organism can't survive a specific environment, he'll probably die until another generation comes in and this one can survive in this environment, passing their genes to the next ones. The lack of information was the knowledge about the genes we have today, that's why most scientists take only the new Darwin theory, that includes the study of genes.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.

1 digestive system

2 stomach

3 bladder

4 carbon deoxide

5 tiger