Someone please help

Correct option is D. An unexpected result occurs during the initial phase of a study; the study is modified in response to this result and the results are interpreted and evaluated.

The writer begins this passage by stating that the ability of birds to fly has long been a source of debate among scientists.

The article then goes on to explain that when a group of students challenged Ken Dial to come up with new data on this hotly debated topic, he devised an experiment to study the evolution of flight by observing how baby Chukars learn to fly. Dial noted the unusual way the little Chukar "used its wings and legs cooperatively" to climb over hay bales during the experiment. Following that, he devised a series of experiments to investigate his discovery.

<h3>Below is the passage mentioned in the question is from Thor Hanson, Feathers by Thor Hanson - </h3>

" At field sites around the world, Ken Dial saw a

pattern in how young pheasants, quail, tinamous,

and other ground birds ran along behind their

parents. “They jumped up like popcorn,” he said,

5 describing how they would flap their half-formed

wings and take short hops into the air. So when a

group of graduate students challenged him

to come up with new data on the age-old

ground-up-tree-down debate, he designed a project

10 to see what clues might lie in how baby game birds

learned to fly.

.............................................................

Ken called the technique WAIR, for wing-assisted

incline running, and went on to document it in a

wide range of species. It not only allowed young

birds to climb vertical surfaces within the first few

weeks of life but also gave adults an energy-efficient

65 alternative to flying. In the Chukar experiments,

adults regularly used WAIR to ascend ramps steeper

than 90 degrees, essentially running up the wall and

onto the ceiling.

In an evolutionary context, WAIR takes on

70 surprising explanatory powers. With one fell swoop,

the Dials came up with a viable origin for the

flapping flight stroke of birds (something gliding

animals don’t do and thus a shortcoming of the

tree-down theory) and an aerodynamic function for

75 half-formed wings (one of the main drawbacks to the

ground-up hypothesis). "

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7 0

1 year ago

The expression 120-15x represents how many invitations Luanne has to address after x days. The expression 120 + 15(7-x) represen

Aloiza [94]

Answer:

not possible.

Step-by-step explanation:

number of invitations luanne has to address after x days = 120-15x

number of invitations Darius has to address after x days = 120 + 15(7-x)

so, if the number of invitations should be the same for both of them,

we have to equate their number of invitations

120-15x = 120 + 15(7-x)

subtracting 120 from both the sides,

-15x = 15(7-x) = 105 -15x

adding we 15x on both sides, we wont find any solution for x.

so, this isnt possible or the question must be wrong.

8 0

3 years ago

Describe the graph that would be used to solve the equation –x2 + 4 = x + 2 using a system of equations. How will you use the gr

gayaneshka [121]

Answer:

The solutions are (-2 , 0) and (1 , 3)

Step-by-step explanation:

∵ -x² + 4 = x + 2

* y = -x² + 4 ⇒ is quadratic represented by parabola

The parabola open downward because coefficient of x² is negative

The x-coordinate of its vertex = -b/2a, where b is the

coefficient of x and a is the coefficient of x²

∴ x = 0/2(-1) = 0

∴ The y-coordinate of the vertex = (0)² + 4 = 4

∴ The maximum point of the parabola is (0 , 4)

∵ -x² + 4 intersects x-axis at y = 0

∴ -x² + 4 = 0 ⇒ -x² = -4 ⇒ x² = 4

∵ x² = 4

∴ x = ±√4 = ± 2

∴ the parabola intersects x-axis at -2 , 2

∵ y = x + 2 represented by a line its slope = 1

It intersects y-axis at 2

∵ x + 2 intersects x-axis at y = 0

∴ x + 2 = 0

∴ x = -2

∴ The parabola and the line intersect each other at

x = -2 and y = 0

To find all the point of intersection between the 2 equations we will solve them as a system of equations

∵ y= -x² + 4 and y = x + 2

∴ -x² + 4 = x + 2

∴ -x² + 4 - x - 2 = 0

∴ -x² - x + 2 = 0 ⇒ × -1

∴ x² + x - 2 = 0 ⇒ factorize

∴ (x + 2)(x - 1) = 0

∴ x + 2 = 0 ⇒ x = -2

∴ x - 1 = 0 ⇒ x = 1

* when x = -2 ⇒ y = -2 + 2 = 0 ⇒ (-2 , 0)

* when x = 1 ⇒ y = 1 + 2 = 3 ⇒ (1 , 3)

The solution graphically

3 0

2 years ago

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