Answer:
D: It explains how much ocean water levels have changed from the past to the present.
Explanation:
The passage states that "At the coldest part of the Ice age, the seas were about 410 feet(125 m) lower than the today. As carbon dioxide levels in the atmosphere naturally rose, Wanless explains, glaciers melted, and the seas rose hundreds of feet." Those two sentences from the passage centrally describe information about the sea and how it has changed throughout the years. Therefore, the answer is D: It explains how much ocean water levels have changed from the past to the present.
hope you understand everything , AD.
Answer:
3 groups of 5
Explanation:
if x is the number of groups of four, and y is the number of groups of five, then 4x +5y =39 (four students per group of four times the # of groups of four, and 5 students per group times the # of groups of five, which should equal the total amount of students, 39). also, x+y=9. (number of each type of group = 9 groups total).
then, use these two equations and solve for y, by "canceling out" x. there are many ways to do this, but i'm going to use subtraction.
4x-5y=39
x+y=9
you want to change the equation
x+y=9
into
4x+4y=36
by multiplying the whole equation by four. because in order to cancel out the x, you need it to equal zero. in the first equation, its 4x.
so its now
4x-5y =39 MINUS
4x+4y=36
___________
y=3
you can check your work because the remaining 6 groups of four (24 total students) plus the 3 groups of five (15 total students) adds up to equal 36
