Answer:
b. ecosystems in a region, species in an ecosystem, and genes and alleles in a species.
Explanation:
Biodiversity has three levels - ecosystem, species and genetic diversity. Therefore, Biodiversity can be defined as the variability among living organisms involving terrestrial, marine, and other aquatic ecosystems, genes and alleles in a species and their ecological complexes such as diversity within species, and between species of the ecosystems.
The sequence of bases on the other half of the DNA molecule would be CTAATGT from left to right, because each cytosine base pairs with a corresponding guanine base, and each adenine base pairs with a corresponding thymine base.
