Electrons in the outer shell are called stable electrons unstable electrons valence electrons

The given blank can be filled with valence electrons.

Explanation:

In chemistry, an outer shell electron known as a valence electron is linked to an atom. This electron can take part in the production of a chemical bond if the external shell is not closed. The existence of valence electrons can assist in finding the chemical properties of an element, that is, whether it take part in bond formation with other elements, and if so, how easily and with how many. A valence electron can be found only in the outmost electron shell in case of the main group element and is found in an inner shell in case of a transition metal.

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.

lysosomes contain a variety of enzymes, enabling the cell to break down various biomolecules it engulfs, including peptides, nucleic acids, carbohydrates, and lipids (lysosomal lipase). the enzymes responsible for this hydrolysis require an acidic environment for optimal activity. hope i !