We take sex for granted — it got us all here, after all. But, it isn't the way of life for everything. Sex, as humans and other animals do it, is bizarre.

Most forms of life on Earth don't have sexes and go about reproducing by cloning complete versions of themselves. Other species have multiple sexes and, like us, combine and shuffle their genes every generation. Sexual reproduction seems an inferior strategy — only half of a parent's genes (the good and the bad) are passed on and it requires a mate. Yet, sex exists and persists.

Male. Female. Why not more? Why not one sex? We asked three researchers:

Why is there sex at all?

• Sarah Otto, theoretical biologist, University of British Columbia: Sex is evolution's answer to an ever-changing world.
• Joan Roughgarden, evolutionary biologist, University of Hawai'i: Male, female: it goes back to size.
• Curtis Lively, evolutionary biologist, Indiana University Bloomington: Sex protects populations from parasites.

• Reef reaction: Erica Pandey on how disrupting oyster reefs appears to unleash carbon dioxide from their shells.
• Blame it on the rain: Toxic algae blooms could become commonplace with increased rainfall due to climate change, from Erin Ross.
• Not annihilated: Ancient DNA analysis finds the Canaanites left a continuous line of descendants, including people in modern day Lebanon, per Jeff Nesbit.

Synthetic biology startups are breaking into the multi-billion-dollar market for industrial enzymes that power reactions for pharmaceutical, chemical, textile, food, and other companies.

How? Synthetic biologists take component DNA sequences that form different enzymes and patch them together to create a biological code. This code can produce new pathways for enzymes to work together or for organisms to produce them. These are then handed to commercial partners who manufacture them in bulk.

What they're after: Every plant, animal, and microbe functions because of enzymes. They catalyze the digestion of food, prevent blood from clotting, and help cells communicate with one another. Wine, bread, cheese, medicines, contact lens solution, laundry detergent, and a long list of other things we enjoy, dislike, and otherwise rely on work because of enzymes. They are, in other words, vital, useful, and lucrative (industrial enzymes are a nearly $5 billion business).

Read more here.

• The unexplained: Ed Cara writes in Undark about what's being done for the millions of Americans suffering from unidentifiable illnesses.
• Firsts: MIT Technology Review broke the news that scientists in the U.S. edited a human embryo for the first time.
• Useful: Ed Yong writes about an app for identifying animals. Too bad I'm not taking my phone into the woods.

When stars die and collapse to form black holes, a powerful explosion — second only to the Big Bang itself — occurs. These gamma-ray bursts take place billions of light years away. Across space and therefore time, they're a window into the early universe that opens for just a few milliseconds to a minute. By the time a telescope is turned, they're typically gone.

Last year though, researchers were able to observe an unusually bright one — GRB 160625B, pictured above— using six telescopes on the ground and in space. They caught it early to enough to measure strong changes in the polarized light of the burst for the first time. "That, in turn, tells us that the release of magnetic energy is an important ingredient in these exotic explosions," says Arizona State University's Nathaniel Butler.

A new picture: Spiraling electrons cause radiation that powers magnetic jets in the first moments of the explosion. The magnetic fields then break down and are largely replaced by matter from the dying star that falls into the black hole and is ejected again. Researchers have known about these two processes but thought only one was responsible. Now, it seems it could be both.