The most common cause of desertification is

A. the construction of dams

B. overgrazing

C. mining

D. drought

In the majority of less developed countries, the major source of energy for domestic use is which of the following

Scientists form a hypothesis based on:

Which of lead protein stricture to the x helix and the b pleated sheet represent?

Griffin performed experiments demonstrating that when live, nonpathogentic, S. pneumoniae (which produce rough-surfaced colonies) are mixed with killed smooth-surfaced S.

Which statement is characteristic of reproduction in humans? 1) The reproductive cells of males and females differ in chromosome number. 2) Males and females produce gametes in the ovaries. 3) Males and females produce the same number of gametes.

All cells contain cell membranes. Which of the following describes the composition of cell membranes? A. Cell membranes are composed of carbohydrate chains, which allow all materials to enter and leave the cell. B.

Hornworts get their name from?

What are surface currents caused by

An investigation was designed to determine the effect of ultraviolet light on mold spore growth. Two groups of mold spores were grown under identical conditions, except one group was exposed only to ultraviolet light, while the other group was grown

How do you plant an avocado seed?