Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period. Index fossils are useful because they tell the relative ages of the rock layers in which they occur.
The answer is C) 3/4
Let's analyze separately each of the traits:
Parental generation: AA x Aa
F1 generation: AA AA Aa Aa
So, all progeny will <span>phenotypically resemble the first parent.
</span>Parental generation: BB x bb
F1 generation: Bb Bb Bb Bb
So, all progeny will <span>phenotypically resemble the first parent.
</span>
Parental generation: Cc x Cc
<span>F1 generation: CC Cc Cc cc
</span>Only 3 (CC, Cc, Cc) out of 4 progeny will <span>phenotypically resemble the first parent.
The genotypes for first two traits will not affect </span>phenotypical resemblance to the first parent. So, it only counts the third trait, for which the chance to have progeny that <span>phenotypically resemble the first parent is 3/4.</span>
Answer:
Certain fossils, called index fossils, help geologists match rock layers. To be useful as an index fossil, a fossil must be widely distributed and represent a type of organism that existed for a brief time period.
Coal seams are far deep underground to be considered for opencast minings. These coal seams require underground mining. Since it is too deep underground, it can be used for mapping and correlation of sedimentary rocks or as a key bed.
