During a camping trip, sierra collected dry branches and broke them into smaller pieces. she then placed the sticks in a fire pit and used a match to light the sticks on fire. next, she propped a metal pan of water over the fire and heated it until the water boiled.

which list correctly describes physical and chemical changes that occurred in this scenario?

a. physical change: breaking sticks
chemical changes: lighting the fire, boiling water
b. physical change: boiling water
chemical change: breaking sticks, lighting the fire
c. physical changes: lighting the fire, boiling water
chemical change: breaking sticks
d. physical changes: breaking sticks, boiling water
chemical change: lighting the fire

D. physical changes: breaking sticks, boiling water

chemical change: lighting the fire

Explanation: Chemical change is defined as a change in which rearrangement of atoms take place and leads to formation of new substances.  

Physical change is defined as a change which leads to change in shape, size or state of the substance changes. No new substance is formed.

a) Breaking of sticks will will only result in the size of paper and thus a physical change.

b) boiling water can will only result in the phase of water and thus a physical change.

c)  Lighting the fire will result into burning of sticks and formation of carbon dioxide and water and thus a chemical change.

the menstrual cycle – higher tier. negative feedback mechanisms affect the production of hormones in the menstrual cycle. oestrogen also stimulates the release of lh (luteinising hormone) from the pituitary gland, which in turn controls the production of progesterone.