The Next Few Questions Refer to the Following Description

question 43

Multiple Choice

The next few questions refer to the following description.
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 gathers 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.
-Which term accurately describes the behaviour of Paramecium species that lack zoochlorellae in an aquarium with light coming from one side only?

• A)positive chemotaxis
• B)negative chemotaxis
• C)positive phototaxis
• D)negative phototaxis

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Definitions:

Marginal Productivity Theory

A principle in economics that suggests that the addition of a unit of labor or capital leads to a change in output, essentially quantifying the extra output produced by adding one more unit of a resource.

Equilibrium Value

The price and quantity at which the supply of an item equals the demand for that item, achieving a balance in the market.

Marginal Product

The additional output that is produced as a result of utilizing one more unit of a variable input, holding other inputs constant.

Equilibrium Quantity

The level of goods or services offered and demanded at the price of equilibrium.