The predominant function of thorns, spines and prickles is deterring herbivory in a mechanical form. Not all functions of spines or glochids are limited to defence from physical attacks by herbivores and other animals.echnically speaking, many plants commonly thought of as having thorns or spines actually have prickles. Roses, for instance, have prickles. Other structures that look alike are spinose teeth, spinose apical process, stiff trichomes and stinging trichomes.
1 This will help the sirloin cook from all angles and sear in the juices.  Grill the steak with lid down for 4-5 minutes depending on thickness. When grilling steaks, you need to resist the urge to open the lid and look.
Since I like medium rare to medium, I wait until it starts to show brown 1/4 to 1/2 way up the side of the steak before flipping the steak. For medium rare on a 1 inch top sirloin boneless steak, total cooking time should be about 8 to 10 minutes.For a 2 inch boneless top sirloin total cooking time of about 18 minutes will give medium rare results.Ideally, you should be using a great instant-read meat thermometer.For medium-rare, cook the steak until the internal temperature is 135 degrees, then remove and allow the top sirloin steak to rest for 5 minutes.Use a good pair of tongs to flip the steak about half way through the cooking time.or medium-rare, cook the steak until the internal temperature is 135 degrees, then remove and allow the top sirloin steak to rest for 5 minutes. Use a good pair of tongs to flip the steak about half way through the cooking time.