The rib cage has 12 pairs of ribs. which cartilage attaches the front ends of the first seven pairs of ribs to the sternum? what is the name of these seven sets of ribs?

The first seven pairs of rib bones (beginning at the top of the sternum) are called "true ribs."  They connect to the spine (by ligaments) at the back, and connect to the sternum by costal cartilage in the front.  Costal cartilage is elastic and allows the ribcage to expand during respiration.

Grilled ham and cheese sandwich: caution: if you’re underaged then have a responsible adult supervising you to prevent any injuries.1. preheat a pan or griddle over medium heat. spread each bread slice with mustard — crust to crust is a must to get full coverage so that each bite is identical. if you don’t like mustard then use whatever else you like.2. use a trio of cheeses in a grilled cheese to achieve perfect harmony: 1 slice of american cheese for gooeyness, 1 slice of aged cheddar for sharpness and 1 slice of provolone or mozzarella for stringiness. if you don’t like these cheeses then use whatever else you like.3. ribbon your meat onto your sandwich to create dramatic height and a smoother bite down. don't just lay the meat flat — it makes for a flat sandwich.4. add anything else you'd like to the sandwich — (just make sure you season them with a bit of salt and 5. spread mayo on the outside of a grilled cheese before it goes into the pan or onto the griddle, which ensures that it will be perfectly golden brown every time.6. place on the griddle; dome your grilled cheese with a metal bowl to create a vortex of heat and ensure the cheese melts without over-toasting the exterior for a maximum of 3 minutes. flip, cover again and cook until the cheese is melted and the sandwiches are golden brown for a maximum of 3 minutes. hope this : )