| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.48 |
| Score | 0% | 70% |
What prevents blood pumped out of the ventricles from flowing back into the heart?
platelets |
|
capillaries |
|
atria |
|
valves |
The heart is the organ that drives the circulatory system. In humans, it consists of four chambers with two that collect blood called atria and two that pump blood called ventricles. The heart's valves prevent blood pumped out of the ventricles from flowing back into the heart.
Saturated fats can __________ LDL ("bad") cholesterol while unsaturated fats can __________ it.
decrease, stabilize |
|
stabilize, raise |
|
raise, decrease |
|
decrease, raise |
Saturated fats can raise LDL ("bad") cholesterol while unsaturated fats can decrease it.
Scavengers break down the dead bodies of plants and animals into which of the following?
producers |
|
simple nutrients |
|
carrion |
|
complex carbohydrates |
Like decomposers, scavengers also break down the dead bodies of plants and animals into simple nutrients. The difference is that scavengers operate on much larger refuse and dead animals (carrion). Decomposers then consume the much smaller particles left over by the scavengers.
Which of these is not a phase in cell division?
cytokinesis |
|
anaphase |
|
megaphase |
|
interphase |
Cell division is the process by which cells replicate genetic material in the nucleus and consists of several phases, beginning with interphase and ending with cytokinesis.
Which of the following is not true of light waves?
are mechanical waves |
|
travel faster than sound waves |
|
can travel through a vacuum |
|
are electromagnetic waves |
Unlike mechanical sound waves that require a physical medium for propagation, light waves are electromagnetic and can travel through empty space. Light waves are also much faster, travelling at 186,000 m/s vs. 343 m/s for sound waves.