I think the third is correct
...
Answer:
a. Genetic variation may be lost from the species as a whole
d. The overall adaptive prospects of the species may decline.
Explanation:
Genetic variations are heritable traits possess by the offspring from it progenitors. This makes the offspring to be an hybrid species because it has inherited the traits of both of his/her parents. In a local population setting goes to extinct, it might be as a result of genetic variation because these inherited variations comes in several ways, some might be adaptability to thrive in adverse weather conditions, some production of specific hormones to combat the current state that its not suitable for them etc. so when a population shows a decline in genetic variation, such population is liable to extinction.
Also, when species can't cope with factors attached with adaptation to a particular ecosystem, (such as exhibiting camouflage in time of danger, during dry season when food scarcity has increased etc) there will be decline in population of the species.
<span>By the late 1960s, scientists had developed the theory of plate tectonics based on a range of new evidence. Technological advances had helped reveal that the ocean floor was not essentially flat, as once assumed, but instead was marked by 50,000-kilometer-long (31,000-mile), 3,000-meter-high (9,800-ft) ridges and 11-kilometer-deep (7-mile) trenches. Scientists found striking patterns related to these features. They found that the youngest oceanic crust is located nearest the mid-ocean ridge and the oldest crust is nearest the trenches. They also detected a pattern of alternating magnetic polarity along the ocean floor, which emanated from the ridge tops. These two pieces of evidence, coupled with the fact that volcanic activity and island-building occurred most commonly at ocean trenches, suggested that new crust was created at mid-ocean ridges and destroyed at ocean trenches. Scientists Harry Hess and Robert Dietz used this evidence to revive and expand Holmes' convection theory into the theory they called "seafloor spreading." Finally, Wegener's notion of continental drift was coupled with a mechanism that could explain the movement of tectonic plates.</span>
Answer:
Welcome to the promised follow-up to our previous examination of the digital television revolution. This week we finally take an opportunity for tortured reference to the revolution being digitized. I suppose everyone is probably making that joke. You heard it here last.
To recap the situation as seen from television-free floor 2B: there are around 275 million TVs in the U.S. These historically were cathode-ray sets receiving analog signals. All stations are to convert to digital signal by mid-June, hastening the obsolescence of analog-only CRTs, the sale of digital converter sets, and the potential change to LCD, plasma, or rear-projection televisions. Last time we learned that CRT recycling is possible and urgent, that Energy Star certifies digital converter boxes, and that Umbra thinks Jon Stewart is cute. Luckily for me I can watch his digital likeness over the internets.
