11
votes
2answers
282 views

Why do pandas have a high probability of giving birth to twins?

According to the BBC documentary "Wild About Pandas", about half of panda birth result in twins. Why do they have such a high probability compared to other mammals? What factor(s) control that ...
5
votes
3answers
964 views

Fetal development, gastrulation and embryonic disc

I am completely confused by the images circulating on the internet of human gastrulation. First, lets see how it happens in deuterostomes. This image depicts the process: (image is from Wikipedia) ...