To test the effectiveness of an allergy drug, scientists begin with a pool of 12,000 allergy sufferers. one randomly selected group of 6,000 subjects is given the drug, and the other 6,000 are given a pill without the active ingredient. they are asked to report their allergy symptoms after 1 week, 1 month, and 3 months of treatment, and samples are also taken to measure the levels of histamines (allergy-related compounds) in the blood. what is the experimental group in this study? 1. 6,000 subjects that are given the drug 2. 6,000 subjects that are given a pill without the active ingredient 3. presence or absence of the drug 4. reports of symptoms and levels of histamines in the blood

What is a universal way that predation benefits the predator? predation increases mate availability. predation in defense of space. the predator gets the energy it needs to survive. the predator keeps parasites from hurting the species.

What are two reasons for why a species might disappear from the fossil record?

For a to be healthy, it has to have lots of different kinds of plants and animals. all of the different types of plants and animals in an ecosystem. name four types of ecosystems from those listed in the video. b) c) d) most living things live here. all living things depend on how an ecosystem like a game of sticks? why should we build new buildings on existing land? name four extinct species from those listed in the video. b) c) d) the best way to wipe out a species is to the largest ecosystem in the world is this percent of the world is covered by water. how many of all species in the world live in the ocean? list five things you can do to increase biodiversity. b) c) d) e) how many species are we losing per hour?