In very dry environments, sand can pile into large dunes. The wind causes ripples on the surface of the sand.
Fossilized ripples of windblown sand
What do fossilized dunes such as the one shown in the photo tell scientists
about the environment?
A. It was once cold and wet.
B. It used to be a glacier.
C. It used to be an ocean.
OD. It was once dry and windy.

Plz ! a frog has a genetic mutation in skin cells that causes part of its skin to turn orange the frog will not pass this genetic mutation onto its offspring because, a. the offspring will inherit skin cells from the other parent. b. mutated skin cells cannot divide and produce daughter skin cells. c. skin cells do not contribute genetic material to sex cells. d. parents do not contribute genetic material to their offspring.

In the diagram below, the northern hemisphere would be in what season at position a a.fall b. winter c.summer d.spring

Astudent from one of the research labs is having trouble preparing a slide for examination and photographing. the bacterial slide that he has brought to you was prepared using a commercially purchased stain. he has asked for your in determining what he is doing wrong so that he can change the lab protocols and continue on with his project. after examining the slide under oil immersion, you determine that no bacteria are present even though the student is able to show you the culture he used to make that slide that has visible growth in the liquid medium. which of the following statements does not explain the fact that there are no bacteria present on the student’s slide? by not allowing a glass slide to completely air dry before heat fixation, the flame will cause the surrounding water to boil and this will damage the bacterial cell. overheating during the fixation step boiled the water within the bacterial cells and resulted in the cells bursting. insufficient heating of the slide did not drive out the thin layer of water and this resulted in minimal bonding between the bacteria and the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide. rinsing with alcohol during the washing step stripped the bacteria off the glass slide.