During an investigation, sam observes the number of hummingbirds that come to his large bird feeder at different times of day. he fills the feeder to the top the first day and counts the number of birds at 6 a. m., noon, and 6 p. m. over ten days. what are the independent and dependent variables in sam’s investigation? the number of birds is the independent variable, and time is the dependent variable. time is the independent variable, and the number of birds is the dependent variable. the type of bird food is the independent variable, and the number of birds is the dependent variable. the number of birds is the independent variable, and the type of bird food is the dependent variable.

You have been asked to lead a demonstration for the undergraduate microbiology lab course about the uses of negative staining when studying bacteria. a "negative" stain does not stain the bacterial cell itself but stains the space between cells. under magnification, the acidic (negativelycharged) nature of the stain will be repelled by the negatively charged bacterial cell wall and willleave the cell colorless in a stained background. negative stains are used primarily to reveal the presence of negatively charged bacterial capsules; therefore, they are also called capsule stains. encapsulated cells appear to have a halo surrounding them. the negative stain procedure does not require heat fixation, which limits any chances of alteration in bacterial cell shape and size. the bacterial suspension is added to a drop of stain, such as nigrosin or eosin, and drawn across the glass slide using a coverslip. nigrosin staining-not safranin staining-of klebsiella pneumoniae will allow for the visualization of the cell shape and the determination of the presence of a capsule. true/false

Compare the depth of field when focusing with low power and high power. which power has the greater depth of field?

Identify the terms using the following picture. principle of dominance item 1 can be described as the . item 2 can be described as the . the "p" represents from one parent.