When scientists say that a theory can never be proven, what are they actually saying?

Agriculture is changing the environment. With increased populations, there is a greater demand for food.

The four pulmonary veins return oxygenated blood to this chamber. What is this chamber?

Shawn will conduct a study by rolling a toy car down a ramp. He plans to set the height of the ramp at 30 centimeters (cm) and record how long it takes the toy car to reach the end of the ramp.

Which is not a disadvantage of the use of solar energy? A. Solar panels are expensive B. Solar energy is available only in the summer C. Solar panels do not work very well D. Solar energy produces greenhouse gases

Suppose 2 alleles on one homologous chromosome are c and d and the other homologous chromosome has alleles c and d. How many types of gametes would occur without crossing-over

What air pollutant that is released due yo human activity? A) carbon dioxide B) nitrogen dioxide C) toxic dioxide D) all of these are air pollutants caused by humans

A group of eye disorders resulting from increased intraocular pressure is

Population i stars are found in what area of the milky way? a. spiral arms b. central bulge c. halo d. globular clusters

An inherited trait which is present even when inherited only from one parent

All the fluid inside the cell except the nucleus is called