Answer the following question given this paragraph: Over 99 percent of all species that ever lived on Earth have gone extinct. Five mass extinctions are recorded in the fossil record. They were caused by major geologic and climatic events. Evidence shows that a sixth mass extinction is occurring now. Unlike previous mass extinctions, the sixth extinction is due to human actions. Q: What percentage of all species that ever lived on earth have gone extinct? Choices: - 25% - 50% - 93 % - 99% A:
99%
Answer the following question given this paragraph: 8.5 Regulation of enzyme activity helps control metabolism. Q: Metabolism is controlled by regulation of what? Choices: - sequence activity - nucleus activity - cell activity - enzyme activity A:
enzyme activity
Q: Answer the following question given this paragraph: With an occluded front , a warm air mass becomes trapped between two cold air masses. The warm air is lifted up above the cold air as in Figure below . Cloudy weather and precipitation along the front are typical. Q: When a warm air mass becomes trapped between two cold air masses, what type of front occurs? Choices: - storm front - obscured front - stationary front - occluded front A:
A: occluded front
Question: Answer the following question given this paragraph: Q: Living things need to take in nutrients so that they can grow and create what? Choices: - protein - plasma - hydrogen - energy A:
Answer: energy
*Question*
Answer the following question given this paragraph: The atomic number of an element is the number of protons in the nucleus of each atom of that element. An atom can be classified as a particular element based solely on its atomic number. For example, any atom with an atomic number of 8 (its nucleus contains 8 protons) is an oxygen atom, and any atom with a different number of protons would be a different element. The periodic table ( Figure below ) displays all of the known elements and is arranged in order of increasing atomic number. In this table, an element's atomic number is indicated above the elemental symbol. Hydrogen, at the upper left of the table, has an atomic number of 1. Every hydrogen atom has one proton in its nucleus. Next on the table is helium, whose atoms have two protons in the nucleus. Lithium atoms have three protons, beryllium atoms have four, and so on. Since atoms are neutral, the number of electrons in an atom is equal to the number of protons. Therefore, hydrogen atoms all have one electron occupying the space outside of the nucleus. Q: An atom can be classified as a particular element based solely on its what? Choices: - light number - spectrum - ability - atomic number A:
**Answer**
atomic number
(Q).
Answer the following question given this paragraph: Amphibians have moist skin without scales. The skin is kept moist by mucus, which is secreted by mucous glands. In some species, the mucous glands also secrete toxins that make the animal poisonous to predators. The blue poison-dart frogs in Figure below are a good example. The toxin in their mucus is used by native people in South America to poison the tips of their hunting arrows. Q: Which group of species is defined as having moist skin without scales? Choices: - fish - mammals - reptiles - amphibians A:
(A).
amphibians