What is a definition of a costimulatory ligand?

Johannesburg kepler, an apprentice of brahe, believed in the heliocentric universe but rejected past astronomers belief in

My question says on my assignment. read the following scenarios and decide which of the properties of life are being described. the first one is. katherine stopped on the way to school to grab some donuts. 2. because a dog cannot sweat, it has to pant in order to stay cool. 3. an elephant trun had no bone but 4,000 muscles. i have no idea what i am supposed to anwer. i can't find the answer in my notes or book that i can understand anyway

Approximately percent of the energy created by cell metabolism is used by the body to carry on its normal functions, such as respiration, digestion, reproduction, muscular movement, circulation, and cellular regrowth.