Question

each morning, she will check how many eggs the chickens have laid. brianna wants sebastian to tell her if this investigation is valid or not.
chicken\ta\tb\tc
amount of food (in grams)\t50\t75\t100
type of feed\tcorn\tgrains\tbeans
frequency of feeding\ttwice a day\ttwice a day\ttwice a day
options:
yes, this investigation is valid because she has three experimental groups.
no, this investigation is not valid because she is not holding anything constant.
yes, this investigation is valid because she is testing three different types of feed.
no, this investigation is not valid because she has more than one test variable (independent variable).

Explanation:

In a valid experiment, there should be a control and variables should be isolated. Here, she has multiple types of feed (independent variable) but no control group and other factors like feeding frequency are the same. To be valid, she should hold some factors constant while changing only the independent variable she wants to test. Since she has multiple types of feed as the independent - variable without proper controls, the investigation is not valid.

Answer:

No, this investigation is not valid because she is testing three different types of feed.