Will give  brainliest , the dark portion of the soil created by the decay of organic matters? is called?

The answer is; Humus  

Humus is found in the topmost layer of the soil where there is decomposing organic matter. This layer of soil has a characteristic color of dark brown to black. This layer of soil also teems with microbial activity and organisms such as earthworms, fungi, and arthropods which  are  significant in the decomposition of the dead organic matter.

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

water at room temperature is flowing through a pipe with pressure taps located 10 ft apart along one section of the pipe, which are connected to a mercury (s=13.6) manometer.