Answer:
double helix
Explanation:
Deoxyribonucleic acid, commonly known as DNA, consists of two long polynucleotide chains composed of four types of nucleotide subunits i.e. A, G, C, T. Each chain is called a strand. Each nucleotide is made up of a pentose sugar, phosphate group and a nitrogenous base.
DNA is a double-helical structure that contains each strand in a spiral or coiled form. This double helix structure forms when two complementary strands are held together by hydrogen bonds. The bonding occurs between the nucleotide base portions of the complementary strands e.g G-C, A-T.
Answer:
Despite the availability of cleaner energy sources, most of the energy used to power American homes comes from the
burning of fossil fuels such as coal and oil. The burning of fossil fuels releases carbon dioxide into the air. Carbon dioxide
is a greenhouse gas that contributes to climate change.
Why do you think it's a challenge to reduce fossil fuel usage in homes in the United States? How could the use of fossil
fuels affect the biodiversity in neighborhoods and the surrounding ecosystems?
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Part B: Conduct Background Research
Research is the first step in engin
The red-legged frog breeds in ephemeral ponds from January through March. Its relative, the bullfrog, breeds in permanent ponds from late March through May. There are two pre-mating isolation mechanism at play here,
1. Ecological isolation: The habitats are different, hence the individuals of both the species do not meet. Ephemeral ponds are temporary ponds that develop during rainy days, while the permanent ponds are full of water throughout the year.
2. Temporal isolation: The time of mating is different for both the species to avoid contact between the individuals of closely related species. Red-legged frogs mate in January to March slot and the bullfrog in the March to May slot.
Answer: The answer is B
Explanation: your popular choices the answers because it’s the only one that makes sense
