Zirconium has an atomic number of 40. how many neutrons are there in an isotope of zirconium-92? a. 40 b. 52 c. 92 d. 132

The diagram shows the structures of horse and cat forelimbs. what does the diagram suggest about the evolutionary relationship between these two mammals? a. they have homologous structures, indicating a common ancestor. b. they have analogous structures, indicating a common ancestor. c. they have homologous structures, indicating that they do not have a common ancestor. d. they have analogous structures, indicating that they do not have a common ancestor.

Answer asap : ( a. how does mucus prevent the entry of pathogens? b. describe two ways white blood cells protect us from pathogens.

Each step in the following process has a yield of 70% ch4 + 4cl2 yield ccl4 +4hcl ccl4 + 2hf yield ccl2f2 + 2hcl of 4.50 mole ch4 reacts what is the total amount of hcl produced