Does anyone know how to do 3 & 4

Someone answer this check out the image!

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.

The table below lists recommended amounts of food to order for 10 party guests. how much of each food item should nathan and amanda order for a graduation party with 55 guests? use the table to answer. item amount fried chicken 16 pieces lasagna 7 pounds deli meats 1.8 pounds sliced cheese 1 and two fifths pounds bakery buns 1 dozen potato salad 2 pounds