Problem 19.54. a martian couple has children until they have 2 males (sexes of children are independent). compute the expected number of children the couple will have if, on mars, males are: (a) half as likely as females. (b) just as likely as females. (c) twice as likely as females.

Which events are likely to be catastrophic to an ecosystem? select the three correct answers. a-hurricane. b-steady population growth. c-seasonal flooding. d-introducing of an aggressive invasive species. e-tsunami.

One statements is an example of a scientific observation. another statement is an example of a scientific explanation. identify the correct statement for each category to illustrate how scientific explanations are inferred from scientific observations.

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.