Arrange these muscle contraction events in the correct order. 1. nerve stimulus
2. myosin attaches to actin causing a twitch
3. acetylcholine binds to receptor
4. calcium channels open
5. sarcoplasmic reticulum releases calcium
6. impulse rides along sarcolemma
7. exocytosis occurs releasing acetylcholine into synaptic cleft
8. calcium binds to troponin moving tropomyosin out of the way
9. impulse enters the cells via the t-tubule
10. acetylcholine vesicles move to endplate

Structures in cells that carry out specific functions.

Can you identify which of the following groups of organisms are, or are not, populations? a. the american bison (bison bison) and grey wolves (canis lupus) currently living in yellowstone national parkb. all of the rainbow trout (oncorhynchus mykiss that) that have ever lived in lake eriec. the group of american bison (bison bison) currently living in yellowstone national parkd. a group of calliope hummingbirds (selasphorus calliope) and a group of rufous hummingbirds (selasphorus rufus) living in the same new hampshire woodse. the northern cardinals (cardinalis cardinalis) living on opposite shores of lake champlain f. all of the whales currently living in the atlantic ocean off cape cod, massachusetts

When water freezes, it . contracts expands