According to this paper, published this week in Science, and described in this article from Psychology Today, the answer you give to the following simple maths question is a predictor of whether or not you are likely to be religious:
Q: If a baseball and bat cost $\$110$, and the bat costs $\$100$ more than the ball, how much does the ball cost?
Leaves don’t just grow equally in all directions, or they would have a regular shape. To understand how a few cells give rise to such complex structures as leaves is described in the abstract of a new paper in Science as “a major challenge in biology”.
The paper presents a new model that shows how leaf shape can arise through feedback between early patterns of oriented growth and tissue deformation, and some experimental evidence to support this model. Researchers filmed individual cells and tracked them as the plant grew. One of the researchers, Professor Enrico Coen, is quoted saying:
The model is not just based on drawings of leaf shape at different stages. To accurately recreate dynamic growth from bud to leaf, we had to establish the mathematical rules governing how leaf shapes are formed.
Professor Douglas Kell, Chief Executive of the Biotechnology and Biological Sciences Research Council (BBSRC), who funded the research, is quoted saying:
This exciting research highlights the potential of using computer and mathematical models for biological research to help us tackle complex questions and make predictions for the future.
Source: First model of how buds grow into leaves.