A student wants to study the effect of sunlight on plant growth. in his experiment, 12 plants receive normal amounts of sunlight, but half are kept under lamps all night. after 6 weeks, the plants' height are measured. Identify the dependent and independent variables.

Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling