What is the species number of protista?

Ectocarpene is a volatile, sperm cell-attracting material released by the eggs of the seaweed ectocarpus siliculosus. its constitution is all the double bonds are cis, and the absolute configuration of the chirality center is s. draw a stereochemically accurate representation of ectocarpene.

Researchers randomly divide participants into groups. each group takes a different amount of omega-3 fatty acid supplements daily for a month. one group receives a placebo. the researchers measure the impact on cholesterol levels in the blood. what is the purpose of random assignment in this experiment? a, to produce treatment groups with similar characteristics b, to ensure that all people with high cholesterol have an equal chance of being selected for the study c, to increase the accuracy of the research results and prevent skewness in the data

The transport tubes for food coming down the plants are called?