What did the phase-contrast microscope allow scientists to study?

a. colorless and transparent material

b. bacteria

c. pond water samples

d. viruses

In van helmont's experiment measuring a growing tree, which possible energy source for the tree's growth was he able to rule out?

What must occur to a shopping cart at rest in order to make it roll forward? A) A force must be provided to overcome gravity. B) Balanced forces must be acting upon the cart. C) An unbalanced force applied to the cart pushing or pulling it forward.

How many bacteria can you have in ten hours if you started with one bacteria?

How do you use the periodic table to recall the lonic charge of an alkali metal, an alkaline earth metal, or aluminum?

Scientific investigations often lead to the formulation of new scientific questions. The observations Charles Darwin's work after he returned home from his voyage prompted him to ask which question? Do living things change over time, and if so, how?

Which is the main source of energy that is shown in the equation?

Which is the least likely reason that pigs have been chosen as donors for humans in the process of xenotransplantation? free of known diseases cost-effective to raise same DNA as humans quick breeding

Why are cell walls important to plants?

Explain the concept of absolute zero.

The cycle repeat when the carbon stored in the atmosphere as carbon dioxide gas is taken