What do periods in the geological time scale represent?

Which of the following is one of the four conditions necessary for natural selection to occur in a population? fewer organisms are born than the habitat can support mutation does not occur organisms have identical characteristics variation is inherited

Which of the following would be a body response when stepping outside without a coat on a snowy day? a. senaceous glands. secrete more senum b. more liquid is transported by the body to the skin fir insulation c. blood vessels in the skin narrow and contract d. blood vessels in the skin expand

Describe your dna model. which part do the straws represent? the pushpins? the paper clips and the black dots you made with the marker?