Find the missing length indicated

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.

Charlie tosses five coins.what is the probability that all five coins will land tails up.

The table shows the number of hours orlando spent at football practice last week. select the appropriate numbers below to complete the model to find the number of hours orlando spent practicing on tuesday and friday.