Sodium is an example of an alkali metal. The alkali metals are found in the leftmost column of the periodic table, known as Group 1. Use the interactive periodic table to explore the properties of the following alkali metals: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs). The animations demonstrate a chemical property common to alkali metals: they react with water. How does the reactivity vary among this group of elements? Why might patterns like this be useful to scientists?

energy and particles

estuaries are the partially enclosed coastal bodies of brackish water formed at the mouth of sea where river meets an ocean. it is a transition zone between river and sea water so estuaries are influenced to both marine environment such as tides, waves and to riverine such as flow of fresh water and sediments. the mixing of sea and fresh water provide high level of nutrients, making estuaries a high product habitats.

many estuaries suffers degradation from a variety of human activities like erosion from deforestation, overgrazing, overfishing, drainage and eutrophication.

so from the above statement answers will be

1. false as estuaries are formed due to both brackish and freshwater.

2.true, due to high productivity estuaries are breeding ground for many marine species.

3. direct and indirect activities of man that contribute to pollution and deposition of sediments.

flooding wildfire landslides climate change the factors listed have an immediate effect on the animal populations found in any habitat. the four factors would lead to a death. b emigration. eliminate c immigration. d mutations.