What structure is indicated by the arrow in this image? 
Photo credit: Carolina Biological Supply Company/Phototake
Definitions:
Relative Frequency
Relative frequency is the proportion or ratio of the number of times a value occurs in a dataset to the total number of observations.
Examination Scores
Quantitative measures that represent an individual's level of performance or achievement on a standardized test or examination.
Frequency Distribution
A summary of how often different values occur within a data set, usually presented in table or graph form.
Cumulative Frequency
The total of a frequency and all frequencies so far in a frequency distribution.
Q17: Bitter cassava is often preferred as a
Q74: Rhizobium radiobacter can be classified as a(n):<br>A)necrotrophic
Q99: A researcher is growing a single plant
Q102: Fungi feed through extracellular digestion and then
Q110: You are studying epiphytic ferns growing in
Q113: How do the two species that make
Q118: An ommatidium is part of a(n):<br>A)single-lens eye.<br>B)compound
Q139: A researcher is studying a mouse strain
Q147: A botanist is studying the growth rings
Q170: Phytochrome prevents seeds of some plants from