A heme group contains four pyrrole rings, which are linked via methene (methine) bridges.

This question is for science: How did trilobites become extinct?

Part One: Wave Facts 1. What type of waves can only travel through a medium?

How do krill provide enough food to sustain whales?

when earths shadow falls on the moon the shadow causes a 1) high tide 2) low tide 3) lunar eclipse 4) moon phase

Ribosomes produce proteins following instructions from the ... A. Cytoplasm. B. Golgi complex. C. DNA.

Many enzymes require metal ions as cofactors due to the inherent properties of the metal ion. Metal ions, when bound to water, will favor the formation of hydroxide ion, which is a strong nucleophile.

What is a vestigial structure? A. A structure that has no use in the organism B. A structure with similar shape but a different use C. A structure that is only in index fossils D. A structure that contains isotopes! apex!

Why is forecasting human population growth more difficult than forecasting population growth in other animals?

You and your physiology instructor are trapped in an overturned ship. To escape, you must swim underwater a long distance. You tell your instructor it would be a good idea to hyperventilate before making the escape attempt.

Thermal vents are found at the bottom of the ocean in the benthic zone.