The sharp, inch-long thorns of the crown-of-thorns sea star are its spines. These spines, unlike those of most other sea stars, contain a potent toxin
If it were discovered that crown-of-thorns sea stars do not make this toxin themselves, then the most likely alternative would be that this toxin is _____. A) derived from the nematocysts of its prey
B) absorbed from the surrounding seawater
C) an endotoxin of cellulose-digesting bacteria that inhabit the sea star's digestive glands
D) injected into individual thorns by mutualistic corals which live on the aboral surfaces of these sea stars
A
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Treatment of drinking water by UV irradiation is effective at ________, but it does NOT remove ________
A) killing bacteria and eukaryotic pathogens / odor- and taste- altering organic compounds B) killing viruses / bacteria and eukaryotic pathogens C) removing order- and taste- altering organic compounds / viruses D) killing bacteria / viruses and eukaryotic pathogens
What are the three different types of skeletal systems?
What will be an ideal response?
Over two decades ago in the People's Republic of China, it was noticed that songbirds were eating rice and millet drying on the grain floors. Since there were large numbers of people to feed, and the population was very near to carrying capacity, it was proposed that the songbird population should be reduced in order to preserve more grain. However, the songbirds also ate a larger number of insects that fed on the rice and millet when it was young. Draw a food web including the above items, indicating energy flow in the direction of the arrows, and representing the general proportion of energy consumed by the breadth of each arrow. State briefly why this decision was disastrous.
What will be an ideal response?
In the "typical" menstrual cycle, day 13 or 14 is when
A) the corpus luteum disintegrates. B) progesterone levels peak. C) menstruation begins. D) ovulation occurs. E) estrogen levels reach their lowest point.