What variable did the experimenter change (independent variable), and what variable did the experimenter observe (dependent variable)?

An independent variable can be controlled by the experimenter to observe it's affect on dependent variable which cannot be changed manually. Rather the dependent variable changes due to the effect of independent variable.  

i it is d i hope it

ans.

gregor john mendel is known for study of inheritance in pea plants. he used garden pea plant for his study, having alternative traits for various characters. he performed cross-breeding in pea plants to check how characters are transmitted between parents to offspring, such as cross between pure tall and pure dwarf plant. mendel studied the inheritance patterns in pea plants for various generations.

thus, the correct answer includes options and f).