<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>
<span>In order to find the value of "a" and "b", first of all perform the multiplication in the parenthesis.
Thus
(3.5x1016) = 3556
and
(2.2x1010) = 2222
As per question;
(3556)x(2222) = 10 axb
By dividing both sides by "10"
we get
(3556)x(222.2) = axb
or
(355.6)x(2222) = axb
by comparing both sides of the equation,
we get that a = 3556 and b = 222.2
or
a = 355.6 and b = 2222
</span>
Answer:
The options
A. the postzygotic barrier called hybrid inviability
B. the postzygotic barrier called hybrid breakdown
C. the prezygotic barrier called hybrid sterility
D. gametic isolation
The CORRECT ANSWER IS A.
A. the postzygotic barrier called hybrid inviability
Explanation:
Postzygotic barrier is a mechanism that hinders reproduction after fertilization and zygote development. Hybrid inviability occurs when a mating between two organism produces a hybrid that can't strive past the embryonic stages.
In Reduced Hybrid Viability there is a lower tendency to survive for individuals whose parents possesses incompatible genetics, which may have result from sexual union of these parents from varying species.
These two frog species in this case study can be separated through the mechanism of the postzygotic barrier called hybrid inviability.
Answer:
B) cAMP
Explanation:
Phosphodiesterase is an enzyme that breaks a phosphodiester bond, for example in molecules such as cAMP and cGMP. So, phosphodiestarases are are regulators of signal transduction: regulate the duration of signaling pathway.
Caffeine is central-nervous-system stimulant and the mechanisms of its action usually are: mobilization of intracellular calcium or inhibition of specific phosphodiesterases.
