Write in short about the structure of the heart?

the heart is divided into four chambers consisting of two atria and two ventricles; the atria receive blood, while the ventricles pump blood. the right atrium receives blood from the superior and inferior vena cava's and the coronary sinus; blood then moves to the right ventricle where it is pumped to the lungs.

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.

just finished the test, the answer is d, greg is the least cost-effective because he charges the most for the project