What situations/conditions lead to the start of primary succession

In a classic experiment using pea shape, mendel conducted two separate genetic crosses. in the first cross the parent plants were “true breeding” for pea shape; one had round peas ( r )and the other had wrinkled (r). the first cross produced a filial 1 generation of all round peas. in the second cross, mendel bred plants from the filial 1 generation. this cross produced different results. out of approximately 1000 plants, about 75% were round and 25% were wrinkled.

Which of the following produces carbon dioxide? a. plants b. animals c. decomposers d. all of the above

List five ways we are indebted to phytoplankton