Put the stages of the formation of a dead zone in their correct order. Large number of fish and other marine life die, surface biomass blocks sunlight and prevents photosynthesis, high levels of microbial activity consume oxygen, excessive amounts of nitrogen and phosphorus promote aggressive biomass growth, surrounding water becomes hypoxic or anoxic, root vegetation and phytoplankton decompose.

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

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the answer to this question is 3.

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.