Gwen is investigating how exercise affects the rate at which she can squeeze a ball. after several minutes, she begins to experience muscle soreness and fatigue. she knows that this means her muscles are beginning to run out of oxygen. which process is likely causing the soreness in her muscle cells?
a. lactic acid fermentation
b. photosynthesis
c. alcohol fermentation
d. krebs cycle

The phlogiston theory in the 17th century attempted to explain burning. the theory stated that combustable objects contained a material called phlogiston, a substance without mass, color, odor, etc. after objects burned, the objects were dephlogistonated and were then in their true form. the phlogiston theory was accepted until the 18th century, when lavoisier proved that combustion requires a gas that has mass. phlogiston is considered a) to be scientific knowledge b) not to be scientific knowledge c) to be proven by scientific method d) to be accepted in the modern scientific community

Which statement describes an endocrine function rather than an exocrine function? a. salivary glands release saliva into the mouth. b. sweat glands release sweat onto the skin c. the pineal gland releases melatonin into the blood. d. esophageal glands release mucus into the esophagus.

Factors that can increase mutation rates a. high temps b. low temps c. food additives d. uv rays