Which life-forms appear to be extinct? a. Sponges, Insects, and flowering plants.
b. Bony fishes, dinosaurs, and mammals
c. Sponges, insects, reptiles
d. trilobites, ammonoids and dinosaurs

Which life-form was most abundant 250 million years ago?
a. dinosaurs
b. reptiles
c. bony fishes
d. trilobites

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

After getting the slide and microscope ready, stella is eager to see the microscopic pond water specimen! she crouches around her microscope and aligns her eye with the microscope’s eyepiece. but she's only able to see a bright white light. at this point, no specimens or cells are visible on stella's pond water slide. after taking a moment to collect her thoughts, stella realizes she can't see any lifeforms because .

Acceleration is a direct result of a.) balanced forces b.) unbalanced forces c.) gravity d.) velocity hurry!