They must have a list of biomes there. When they say which one is endangered they mean which one is likely to no longer exsist after an amount of time.
Answer:
B. In an area where a glacier has retreated
Explanation:
Primary succession, starts at a lifeless area where it has been affected by lava flood and/or retreated glacier therefore the answer is B.
Answer:
B (2nd Option): DNA is single-stranded
Explanation:
A is correct: DNA is indeed found in the nucleus of eukaryotes.
B is incorrect: Although there can be single strands of DNA (ssDNA), DNA is usually double-stranded which is how it forms its characteristic double-helix shape.
C is correct: Deoxyribose is indeed the sugar in DNA (Deoxyribonucleic Acid)
D is correct: The two single ringed nitrogenous bases in DNA are thymine and cytosine, while the other two (Adenine and Guanine are double ringed.
Hope this helped!