Simple leaves have a single leaf on a petiole, or stem, while compound leaves have more than one leaflet on a petiole. This unknown leaf can be identified using the dichotomous key. Compound Leaves Simple Leaves * Unknown Leaf Identification SA Characteristic ia Compound leaf 1b Simple leat Za Leal pointed at the tip 7b Leal rounded at the tip Ja Leal length four or more times greater than width 3b Leaf length less than four times the width Leal ponted at the tip 4b Leaf rounded at the tip Ungnada speciosa Sophora cundiilora Swix nigra Arbutus alapensis Quercus lacew Which tree does the unknown leaf come from? A. Ungnadia speciosa
B. Sophora secunditfora
C. Sali nigra
D. Quercus laceyi​

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the answer is b.) hydrogen bonds between bases.

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.