Answer:
Hello!
Here's the correct order of events:
- Development of photosynthesis
- Free oxygen in the atmosphere
- Development of eukaryotic cells
- Sexual reproduction
Explanation:
Development of Photosynthesis:
3.5 billion years ago, the first photosynthetic bacteria emerged. They used near infrared light to form sulfates or sulfur compounds instead of oxygen.
Free oxygen in the Atmosphere:
Later, about 2.7 billion years ago, cyanobacteria or blue-green algae began to perform oxygenic photosynthesis by utilizing visible light.
Development of Eukaryotic Cells:
The first eukaryotic cell probably appeared around 2 billion years ago. The evolution of eukaryotes is explained by the endosymbiont theory. The endosymbiotic theory explains that eukaryotic cells formed when an ameoba like organism engulfed cyanobacteria and a microorganism capable of cellular respiration that later evolved into chloroplasts and mitochondria respectively.
Sexual reproduction:
The origins of sexual reproduction are still widely debated upon; some studies claim the event occurred 1.2-2 billion years ago.
Answer:
During meiosis, homologous chromosomes may exchange genetic material during a process called "crossing over."
Interphase, prophase, Metaphase, anaphase, telophase
So: both parents' genotypes (concerning baldness gene) are the same: Bb. Possible genotypes of an offspring: BB, Bb, Bb, bb . bb means non-bald girl or boy. Bb means bald boy or non-bald girl. BB means bald boy or girl. there is 25% chance of conceiving a child with a genotype BB. But there is also 50% chance of conceiving a girl. So the answer is: 25% x 50% = 12,5%