Nitrogen fixation is a. the conversion of gaseous nitrogen into an organism friendly form (ammonia (nh3). b. preplanned setting of atmospheric levels of nitrogen at 78% c. stabilizing elemental nitrogen into a gaseous two-atom molecule (n2) d. the reduction of nitrate (no3-) to gaseous nitrogen. e. the repair of d. n.a. by adding nitrogen to the organism's diet

After reading the paragraph below, answer the questions that follow. researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. the robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract. all of the cardiac cells working together can cause the robot leg to move in a way that individual cells could not. this is an example of a. emergent properties of cells. b. energy flow through an ecosystem. c. adaptation. d. internal environment regulation.

Which of the following statements is most likely correct about a rock belonging to the jurassic age and a rock belonging to the cambrian age? options: 1) they have identical fossils of organisms that have evolved over time. 2) both have animal fossils preserved in them due to weathering and erosion. 3) they contain different fossils because life on earth has changed through time. 4) the fossils in them were formed on the surface of earth due to exposure to sunlight.

What is usually (but not always) related to the metabolic processes of living organisms in its organic form?