A farmer who grows blackberries has found his harvest to be lower than usual. He suspects that some animals are eating the berries before he can pick...

A farmer who grows blackberries has found his harvest to be lower than usual. He suspects that some animals are eating the berries before he can pick them. The farmer thinks it may be either birds (landing on the bushes to feast on berries) or rodents (climbing the bushes from below to munch on berries). He decided to first test the hypothesis that birds are eating berries, and consults with a local expert on how best to prevent the birds from eating berries. He has 8 fields with 10 rows of berry bushes in each field. In one of the fields , he covers half of the rows with nets that will prevent birds from landing on the bushes, and he leaves the other half uncovered. Over the courses of 8 weeks, he counts the berries harvested from each row of bushes in the test field. 

1) The independent variable is number of rows and the depend variable the number of berries harvested

2) the independent variable is presence/absence of nets and the dependent variable is number of rows

3) the independent variable is number of berries harvested and the dependent variable is presence/absence of nets

4) the independent variable is presence/absence of nets and the dependent variable is number of berries harvested. 

What are the experimental units in his experiment 

- the birds 

-the Rows of bushes

- the BlackBerry bushes

-the fields

What is the control group in this experiment 

-The uncovered rows

-the covered rows

- the other 7 fields

-there is no control group

The farmer considered to be well designed. After 8 weeks he finds there is no differences between groups and the berry harvest was still lower than in previous years. What can he conclude about his hypothesis. 

- rodents are eating the berries

-birds are eating berries

-birds not eating berries 

-the results do not adress the hypothesis