This fossil trilobite and this living blue crab both have a limb structure called a biramous limb. What best explains why both species have biramous limbs? A. It is impossible to say. Fossils are very old, so we cannot make observations of the trilobite’s ancestors, and we cannot explain its body structures.

B. It is impossible to say. Fossils are very old, so we cannot make observations of the trilobite’s ancestors, and we cannot explain its body structures.

C. All species have their own specific body structures, so it is a coincidence that this trilobite and blue crab each happen to have the biramous limb structure.

D. The trilobite and blue crab are different species, so they must not share an ancestor population. They inherited their biramous limb structure from separate ancestor populations.
YALL HELP PLS

I think the answer is b

Explanation:

b The trilobite and blue crab both share the same ancestor population that had a biramous limb. They inherited this structure from the ancestor population. c All species have their own specific body structures, so it is a coincidence that this trilobite and blue crab each happen to have the biramous limb structure.

cuz he's blad

explanation:

"menstrual cycle is a complex cycle that consists of several processes. order of occurrence of steps in menstrual cycle are as follows:

1. high progesterone levels maintain the endometrium lining of the uterus.

2. endometrium lining breaks down and low levels of estrogen stimulate the pituitary to release fsh and lh.

3. fsh and lh stimulates the follicles to develop and the oocyte to produce estrogen.

4. rising estrogen levels suppress fsh production and development of other follicles.

5. a spike in lh causes follicle to rupture.

6. a breakdown of corpus luteum causes progesterone level to drop."