According to the scientific view, about how many years ago did life on earth begin?

A. 3.5 million years ago

B. 3.5 billion years ago

C. 350,000 years ago

Why are the leaves of many plants broad and flat? A. To prevent water loss from transportation B. To transport nutrients through the plant C. To obtain energy by breaking bonds in glucose D. To capture light energy used for photosynthesis

Food moves along the digestive tract as the result of contractions by

What should a beginner do during the initial phase of an exercise program?

During the signal transduction process, the signal often triggers a signal transduction cascade. For example, a single activated protein A molecule activates hundreds of protein B molecules, and so on, until a cellular response occurs.

What types of information caused scientists to add the level of domain to the system of classification?

Your alien friend from planet Xenon is visiting and wants to learn how to breed pea plants. You show your friend a recent batch of pea plants with purple flowers that you grew by crossing plants that had purple flowers with plants that had white

The green stem ant has three (autosome) chromosomes. During meiosis, chromosome 1 and 3 separate normally, but chromosome 2 homologs do not separate during meiosis I. Meiosis II happens normally. What will the resulting cells of meiosis look like?

A population is growing at a rate of 2,4,8, 16, 32. Which type of growth does this describe?

Which epithelial tissue type is most often found lining large ducts, such as those of the salivary glands or pancreas?

Evolution led to certain fishes, such as lung fishes to adapt to terrestrial mode of life. These fishes were the ancestors of modern amphibians. Which evolutionary mechanism is represented by this example?