Adependent variable is
a. directly changed by the experimenter.
b. manipulated by changes to the independent variable.
c. a variable that is kept constant.
d. a variable that is used as a control.

Acladogram is a branching diagram that represents suggested evolutionary relationships among organisms based on the presence of unique traits. a scientist discovers a new organism that lacks limbs and does not have a true backbone. the organism lays eggs to produce offspring and has a cartilage-like rod known as a notochord running along its dorsal surface. on the cladogram below, select the species to which the newly discovered organism is most closely related.

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes

Explain what a zygote is. use the terms egg cell, sperm cell, and fertilization in your explanation.