Sponges and Ctenophores Have Both Been Proposed as Basal Metazoans

question 19

Multiple Choice

Sponges and ctenophores have both been proposed as basal metazoans. Which of the following types of data support the idea that sponges are the basal group?

• A) sequences of cadherin genes, cleavage type, structure of collar cells, and bilateral symmetry of adults
• B) sequences of collagen genes, bilateral symmetry of adults, cleavage type, and fossil steroids
• C) recent phylogenomic evidence, fossil steroid evidence, molecular clock, lack of tissues in sponges, and structure of collar cells
• D) structure of collar cells, bilateral symmetry of larvae, sequences of cadherin genes, and molecular clock

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Definitions:

Cerebrospinal Fluid

A transparent, colorless fluid located in the brain and spinal cord, serving as a protective padding for the brain's cortex, offering fundamental mechanical and immunological defense.

Spinal Cord

The cylindrical bundle of nerve fibers and associated tissue that is enclosed in the spine and connects nearly all parts of the body to the brain.

Parietal Lobe

A region of the brain located behind the frontal lobe, responsible for processing sensory information related to touch, pressure, and spatial orientation.

Sympathetic Nervous System

is a part of the autonomic nervous system that orchestrates the body's rapid involuntary response to dangerous or stressful situations, often referred to as the 'fight or flight' response.