How might you cause an endothermic chemical change to begin keep going?

The least penetrating form of radiation is

Assume you measured the mass of the cart to be (500 ± 1) g and the mass of the additional mass you put on the cart to be (500 ± 1) g as well. since the scale you are using in the lab cannot measure objects heavier than 600g you will have to sum up individual pieces and propagate the error. so what would be the mass and the standard error of the cart and the mass

What surface does the epithelial tissue cover? a. the surface of the body b. lines internal organs c. forms many glands d. all of the above