Most Modern Echinoderms Assume a Mouth-Down Feeding and Locomotion Posture

question 26

Multiple Choice

Most modern echinoderms assume a mouth-down feeding and locomotion posture.Members of the class Crinoidea are an exception.They are attached,mouth-up,and feed using tube feet to trap food from the water column.Recent molecular analyses show the Crinoidea to be basal to other extant classes.Which of the following help to explain these observations?

• A)Feeding and locomotion posture is not a phylogenetically significant character as all fossil echinoderms assumed a mouth-down posture.
• B)The mouth-up posture must be an ancestral character.The mouth-down posture evolved secondarily.
• C)The molecular analyses must be in error.The mouth-up posture is phylogenetically significant and must have been derived secondarily.
• D)There is no reasonable explanation for these observations at this time.

Recognize and calculate the mean and median for both symmetric and skewed distributions.

Grasp the concept of variability and how it is measured through variance, standard deviation, and range.

Understand how extreme values or outliers affect the mean and median.

Comprehend the calculation and interpretation of the standard deviation and its changes under data transformation.

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Definitions:

Transaction Posted

The act of recording a financial transaction in the accounting records of a company.

Debit

A ledger entry contributing to the growth of assets or lessening of liabilities in a company's financial statement.

Credit

The provision of resources (such as money) by one party to another party where the second party does not reimburse the first party immediately, but promises either to repay or return those resources at a later date.

Transposition Error

A common accounting mistake where numbers are mistakenly reordered, leading to inaccurate data entry.