Use the Following Information to Answer the Question

question 59

Multiple Choice

Use the following information to answer the question.
Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways:
(1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae.
The motility that permits P. bursaria to move toward a light source is provided by ________.

• A) pseudopods
• B) a single flagellum featuring the 9 + 2 pattern
• C) many cilia
• D) contractile vacuoles

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Definitions:

Correlational Study

A research method that examines the relationship between two or more variables to determine if they move together in any way.

Ex Post Facto

A Latin term meaning "from after the fact," often used in legal contexts to describe laws that apply retroactively.

Observational

Pertains to a research method in which the investigator observes subjects without manipulating the study environment or the subjects themselves.

Experimental

Involving a trial or test to discover something unknown, often conducted under controlled conditions.