Answer:
1. Polygenic
2. RW
Explanation:
1. A polygenic trait is regulated by more than one gene. The phenotype of the organism is regulated by sum total of all the dominant alleles of these genes. Therefore, these traits exhibit continuous variations and are called quantitative traits. Skin color in humans is an example as it is regulated by more than one genes and the phenotype is determined by total dominant alleles of these genes.
2. If allele R gives red phenotype and the W gives white phenotype, a cross between RR (red) and WW (white) would produce all the cows with RW genotype. The parent cow with RR genotype would form all the gametes with R allele while all the gametes from WW parent would have one copy of the W allele. The random fusion of gametes with R and W alleles would produce progeny with RW genotype.
The correct answer is C.
In the aquarium, the water plants would provide the O2 molecules necessary for the snail's metabolism and the snail would release the CO2 molecules that are a byproduct of his metabolism into the container. The CO2 would later be used by plants to make sugar in the process of photosynthesis, releasing more O2 and the cycle of two gases would be completed.
Estuaries. Brackish water condition commonly occurs when fresh water meets seawater. In fact, the most extensive brackish water habitats worldwide areestuaries, where a river meets the sea. The River Thames flowing through London is a classic river estuary.
