The element was poisonous to the first forms of life on earth until they evolved to take advantage of it by using cellular respiration. what is it? a. hydrogen b. nitrogen c. oxygen d. sulfur

After reading the paragraph below, answer the questions that follow. researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. the robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract. all of the cardiac cells working together can cause the robot leg to move in a way that individual cells could not. this is an example of a. emergent properties of cells. b. energy flow through an ecosystem. c. adaptation. d. internal environment regulation.

All individuals have two alleles for a given trait. according to mendel's these alleles are passed down one each from both mother and father.

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry