Scientists believe that of species that once existed on earth are now extinct.
a. about three-quarters
b. nearly half
c. about 40%
d. over 99 percent

The correct answer is D. Over 99 percent

Explanation:

Life on Earth has existed for 4.28 billion ago and during this time billions of species have emerged including bacterias, fungi, plants, animals, etc. However, due to evolution, changes in the environment and massive extinction events most species that lived in other geological periods have completely disappeared or extinct. Indeed it is estimated by biologists and scientists that over 99% of the species that ever existed on Earth do not live today or are extinct this has been proposed based on the millions of fossils discovered that suggest multiple species that cannot be found nowadays and evidence that shows many more species are extinct and there is no or little evidence about them. Therefore over 99 percent of species that once existed on Earth are now extinct.

the two answers are a, the population of birds with large beaks will increase on the island, and c, the trait for large beaks will be passed on to future generations through natural selection. the reason for that is because if the birds that have beaks developed for eating small seeds lose all of their food, they will go hungry and eventually starve because they physically cannot eat the large seeds, therefore making the population of large beaked birds higher. also, if the trait of large beaks are dominant on the island over small beaks, then over time the large beaked birds will reproduce more and more, while the smaller beaked birds will reproduce less and less because they can't survive with the food provided. that leads to the trait of small beaks disappearing and the trait of large beaks taking over the island.

answer-

the statement that f(x) = |x+a| + b has exactly one x-intercept is sometimes correct.

solution-

it solely depends on b, whether the function will have one or two or zero x intercept.

this plot of the given function, f(x) = |x+a| + b will be the basic absolute value graph i.e v shape, with vertex translated to (-a, b), instead of origin.

1-   if b is zero, the graph will have exactly one x-intercept, at x= -a

2- if b is positive, the whole graph will be above the x-axis, hence it will have no x-intercepts.

3- if b is negative, the graph will be below the x-axis, hence it will have two x-intercepts.

∴ the statement is sometimes true.