Shells are considered biotic because they come from living things. Biotic describes something living or use to be living such as plants and animals. So shells are considered biotic because they come from a living organism.
~~~~~~~~~~~~~~~~~~~
Hope that helped:)
~~~~~~~~~~~~~~~~~~~
Answer:
Alleles for feather colour exhibit incomplete dominance or co-dominance.
50% gray offspring + 50% black offspring
Explanation:
<em>It means that the alleles for feather colour in the hen exhibit incomplete dominance or co-dominance over one another.</em>
Assuming the allele for white colour is B, white colour will be b while the heterozygote Bb gives the gray phenotype.
Gray rooster + gray hen = 15 gray chicks, 6 black chicks and 8 white chicks.
15:6:8 is roughly 2:1:1 which is phenotypic ratio obtainable from crossing two heterozygous individuals as pointed out by Mendel.
Bb x Bb = 1BB, 2Bb, and 1bb
Crossing the gray rooster (Bb) with a black hen (bb):
Bb x bb = Bb, Bb, bb, and bb
= 2Bb (gray):2bb (black)
50% of the offspring will be gray while the remaining 50% will be black.
The answer is Gemini trust me