Question

1. which of the following statements about rna is false?

a) it is single - stranded
b) it contains ribose
c) it is more stable than dna
d) it can catalyze reactions

1. the miller - urey experiment produced:

a) amino acids
b) nucleic acids
c) proteins
d) carbohydrates

1. endosymbiotic theory explains the origin of:

a) mitochondria and chloroplasts
b) the nucleus
c) multicellularity
d) the first prokaryotic cells

1. the transition from single - celled to multicellular life:

a) happened only once in the history of life
b) was a simple, straightforward process
c) occurred independently in different lineages
d) did not require any new forms of communication between cells

Explanation:

• Question 7: DNA is double - stranded and more stable than RNA. RNA is usually single - stranded, contains ribose, and some RNA (ribozymes) can catalyze reactions.
• Question 8: The Miller - Urey experiment simulated early Earth conditions and produced amino acids.
• Question 9: The endosymbiotic theory proposes that mitochondria and chloroplasts were once free - living prokaryotes that were engulfed by a larger cell.
• Question 10: The transition from single - celled to multicellular life happened multiple times independently in different lineages and was a complex process that required new forms of cell - to - cell communication.

Answer:

1. c
2. a
3. a
4. c