Lichens represent symbiotic associations of fungi and (a) roots (b) roundworms $(c)$ water molds (d) green algae.

Mutualistic associations of plant roots and fungi are called ________.

Chlorine is often added to swimming pools to control microorganisms. If the level of chlorine rises above 3 ppm (parts per million), swimmers will experience burning eyes and skin discomfort. If the level drops below 1 ppm, there is a possibility that the water will turn green because of a large algae count. Chlorine must be added to pool water at regular intervals. If no chlorine is added to a pool during a 24-hour period, approximately 20% of the chlorine will dissipate into the atmosphere and 80% will remain in the water.

(a) Determine a recursive sequence $a_n$ that expresses the amount of chlorine present after n days if the pool has $a_0$ ppm of chlorine initially and no chlorine is added.

(b) If a pool has 7 ppm of chlorine initially, construct a table to determine the first day on which the chlorine level will drop below 3 ppm.

Several years ago, many botanists classified algae as plants. They also classified flagellated Euglena as photosynthetic protozoa. Algae are now categorized as protists, and Euglena is now considered an alga. What do these changes tell you about the category systems of living things?

The Akashi-Kaikyo Bridge in Japan is about $1 \frac{4}{9}$ times as long as the Golden Gate Bridge in San Francisco. The Golden Gate Bridge is about 9,000 feet long. About how long is the Akashi-Kaikyo Bridge?

What adaptive advantage do you think different types of chlorophylls confer on algae? Explain.

Two stars of the LA Clippers and the Golden State Warriors are very different when it comes to making free throws. ESPN.com reports that DeAndre Jordan makes $81 \%$ of his free throw shots while Kevin Durant makes $62 \%$ of his free throws. ${ }^5$ Assume that the free throws are independent and that each player shoots two free throws during a team practice. a. What is the probability that DeAndre makes both of his free throws? b. What is the probability that Kevin makes exactly one of his two free throws? c. What is the probability that DeAndre makes both of his free throws and Kevin makes neither of his?

On the short lines provided, identify each numbered word group in the following paragraph as a sentence fragment $(F)$, a run-on sentence $(R)$, or a complete sentence $(S)$. Then, on the long lines, correct each sentence fragment and run-on sentence.

Example $\quad R$ [1] You might think mythology and folklore are just a bunch of stories from the past these stories, however, are alive today.

1. You might think mythology and folklore are just a bunch of stories from the past. These stories, however, are alive today.

[9] Mythology and folklore have also given us sayings, one is about "the goose that lays the golden eggs."

Algae generally contain some type of a. spore b. chlorophyll c. locomotor organelle d. toxin

Which of the following organisms can perform photosynthesis

(a) Algae
(b) Fungi
(c) Rhizobium
(d) Virus

What is Sanskrit, and how was its use an important part of the Gupta golden age?

Read the passage. Then answer the question. In 1883 the volcano on Krakatoa Island in the South Pacific erupted with one of the most violent explosions ever witnessed. All living things on islands many kilometers away were destroyed. Most of the island itself disappeared, and what remained was covered with sterile ash. Over the next 50 years scientists studied the recovery of life on Krakatoa. Within a year, they discovered a species of spider. By 1886 the ground was covered with algae, ferns, and flowering plants. A survey in 1933 found a fully functioning rain forest with birds, bats, snakes, even crocodiles. Differentiate between the ecosystem on Krakatoa after this recovery and the ecosystem before the eruption.