Determine when to put on disposable gloves for work in the lab. Select one: A. Before entering the laboratory room B. Before handling any glassware or chemicals for the expe C. After setting up all the glassware but before handling che D. After cleaning all the glassware for the experiment

What are scientists who study fossils called? ( a ) astronomers. ( b ) biologists. ( c ) geologists. ( d ) paleontologists.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)

The reactions of photosynthesis occur in the of plant cell? a.mitochondria. b. lysosomes. c. chloroplasts. d. chlorophyll