Why do higher trophic levels is most ecosystem contain fewer organisms than lower trophic levels

With less energy at higher trophic levels, there are usually fewer organisms as well

Explanation: Organisms tend to be larger in size at higher trophic levels, but their smaller numbers result in less biomass. Biomass is the total mass of organisms at a trophic level.

indium, and thallium have three electrons i think

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.