An artery ______________________.
c. usually (but not always) carries oxygen-rich blood
The correct answer is: sexual reproduction
Sources of genetic variation are different:
• Genetic mutations-random and rare events that occur within the genome and contribute to variations among individuals (or population). Mutations might be neutral, harmful or beneficial when they form new alleles favored by natural selection.
• Crossing over (genetic recombination)-event that occur during the meiosis (cell division that creates gametes)
• Random segregation during meiosis
• Random fertilization
• External source such as transposable genetic elements or retroviruses.
Plants began to appear around 470 million years ago. Dinosaurs became extinct about 65 million years ago, so thats not a choice. Prokaryotes first appeared on Earth almost 2 billion years ago, so thats not a choice either. Age of the Reptiles began about 252 years ago, so this could be a choice. Eukaryotes formed around 1.5 billion years ago, so probably not a possible choice. Based of the data I provided you, C is the most likely answer. Hope this helps!