What is the expected completion time for the project and what is the probability that the project will take more than 30 days to complete?

What is the size of the matrix resulting from

Two lines parallel to the same plane are parallel to eachother

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.