Which of the following are decomposition reactions? 1. ch4 (g) + o2 (g) → co2 (g) + h2o (l)
2. cao (s) + co2 (g) → caco3 (s)
3. mg (s) + o2 (g) → mgo (s)
4. pbco3 (s) → pbo (s) + co2 (g)
Then the multiple choice options are:
A. 4 only
B. All are decomposition reactions
C. 2,3 and 4
D. 2 and 3

Idon’t know how to solve this question

Effect of rotenone and antimycin a on electron transfer rotenone, a toxic natural product from plants, strongly inhibits nadh dehydrogenase of insect and fish mitochondria. antimycin a, a toxic antibiotic, strongly inhibits the oxidation of ubiquinol. (a) explain why rotenone ingestion is lethal to some insect and fish species. (b) explain why antimycin a is a poison. (c) given that rotenone and antimycin a are equally effective in blocking their respective sites in the electron-transfer chain, which would be a more potent poison? explain.

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt