In clinical trials of medicines why is one group of volunteers given a placebo

Suppose that the cells of seed plants, like the skin cells of humans, produce a pigment upon increased exposure to UV radiation. Rank the following cells, from greatest to least, in terms of the likelihood of producing this pigment. 1.

How would you describe the shape of the Elodea leaf cell?

Which branch of anthropology involves excavating prehistoric sites or studying historic sites to understand early human ways of life?

What does it mean for the human and the wolf to walk separate but parallel path

Scientists studying human genes could obtain DNA from a cell's A. vacuole B. ribosome C. nucleus D. cytoplasm

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?