Desert plants commonly have small wax coated leaves to prevent moisture and water from evaporating. It is an important feature in desert plants to adapt to the arid climate. The wax on the leaves also protect the leaves from the chilling temperature of the desert at night.
I think that it's cannot include supernatural explanations, or C.
If i got it wrong sorry
At divergent boundaries, plates separate, forming a narrow rift valley. Here, geysers spurt super-heated water, and magma, or molten rock, rises from the mantle and solidifies into basalt, forming new crust. Thus, at divergent boundaries, oceanic crust is created.
Here are the possible answers for the following questions above:
1. H-CC-H (name) - C<span>. ethyne
</span>2. cyclic compound with both saturated and unsaturated characteristics - G<span>. benzene
</span>3. CnH2n - E<span>. general formula for alkenes
</span>4. reaction typical of unsaturated hydrocarbons - A<span>. addition
</span>5. CnH2n-2 - F<span>. general formula for alkynes
</span>6. series name of hydrocarbons with triple bond - D<span>. alkyne
</span>7. CnH2n+2 - B<span>. general formula of alkanes</span>
Equation for Half life :
A = a(0.5)^(t/h)
A is current amount, "a" is initial amount, h is halflife, t is time
5 = 40(0.5)^(t/1.3x10^9)
5/40 = (0.5)^(t/1.3x10^9)
take the log of both sides , power rule
Log(5/40) = (t/1.3x10^9) * Log(0.5)
(1.3x10^9) * Log(5/40) / Log(0.5) = t
3.9x10^9 years = t
And if you think about what a half life is, the time it take for the amount to reduce to half.
40/2 = 20
20/2 = 10
10/2 = 5
It went through 3 half-lifes
3 * 1.3x10^9 = 3.9x10^9 years