What is a tough, rigid, outer covering that protects some cells and gives them shape?

True or False the way energy flows through an ecosystem can be shown through a food web

Which element could not form in the sun and would have to be formed in a supernova? a. hydrogen (atomic number 1) b. helium (atomic number 2) c. oxygen (atomic number 8) d.

A gas at a fixed volume had a temperature change from 87.00 K to 65.25 K. At 65.25 K, the pressure was recorded as 18 Pa. What was the initial pressure?

True or False ... Renewable resources have disadvantages. If so what are the disadvantages?

Technology applies the principles of science to particular problems. True False

What is the empirical formula of a substance that is 53.5% C, 15.5% H, 31.1% N?

What is the lowest layer of the atmosphere and what is its highest altitude?

An atom that has 84 protons and 86 neutrons undergoes a reaction. At the end of the reaction, it has 82 protons and 84 neutrons. What happened to the atom?

A compound of material formed by a chemical is known as?

Which of these molecules experience london dispersion force?