Which of the following has caused 100,00 year cycles of ice ages in the past?

A. An increase in sun spots

B. Several major volcanic eruptions

C. changes in earths orbit and the tilt of its axis

D. continental drift

What caused the mass extinction of the permian period

How many covalent bonds would you expect a neutral carbon atom to form in an organic compound?

A student examines a thin section of an onion-root tip and records the number of cells that are in each stage of the cell cycle.

What skull structure must the axons from the olfactory epithelium pass through in order to get to the olfactory bulbs?

What type of inheritance is always dominant and both genes are expressed

Chimpanzees reproduce sexually, and sponges reproduce asexually. What disadvantage do chimpanzees have compared to sponges

What is the immune system? A. The group of cells and organs that protect the body from disease. B. A group of cells that undergoes apoptosis to protect the body. C. A group of organelles that digest particles that invade the cells. D.

Seth runs up 3 flights of stairs. the first climbs takes him 12 seconds. his second climb takes him 15 seconds. Has the power done been affected?

What is the best description of a molecule

What are Designer Babies? What are the pros and cons?