Which of the following statements is true of evolution? a. evolution does not always progress in one set direction. b. earth's present-day species evolved from older, identical species. c. limited resources discourage the evolution of species. d. all of these

B. Earth's present-day species evolved from older, identical species.

The evolution is the change or modification in the characteristics of a species over genration due to the process of adaptation and natural selection. The statement "Earth's present day species evolved from older, identical species is true about evolution". As, proposed by Darwin evolution is "descent with modification", which means that in a process of evolution species change and give rise to new species over generation. He proposed that newly evolved life forms can be traced back to their common ancestor.

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.