| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.50 |
| Score | 0% | 70% |
Menstruation occurs when:
the ovum becomes fertilized |
|
the zygote is formed |
|
the fetus is formed |
|
the ovum fails to become fertilized |
If the ovum fails to become fertilized, the lining of the uterus sloughs off during menstruation. From puberty to menopause, this cycle of menstruation repeats monthly (except during pregnancy).
Which of the following substances gives up positively charged hydrogen ions (H+) when dissolved in water?
alkaline |
|
acid |
|
base |
|
solution |
An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.
When two air masses meet and neither is displaced, what kind of front is present?
warm |
|
occluded |
|
stationary |
|
cold |
When two air masses meet and neither is displaced, a stationary front is created. Stationary fronts often cause persistent cloudy wet weather.
In the heart, blood flows from the right __________ to the lungs then back to the heart via the left __________.
atrium, ventricle |
|
ventricle, atrium |
|
atrium, atrium |
|
ventricle, ventricle |
The two largest veins in the body, the venae cavae, pass blood to the right ventricle which pumps the blood to the lungs through the pulmonary artery. Blood picks up oxygen in the lungs and returns it to the left atrium via the pulmonary vein.
An endoskeleton (internal skeleton) is a charateristic of __________ animals, including humans.
sentient |
|
arthropod |
|
spiny |
|
vertebrate |
An endoskeleton (internal skeleton) is a charateristic of vertebrate animals, including humans.