Answer key
Lichen: symbiotic association between a unicellular algae and a fungus. Spores: are cells that fall to the ground, and when conditions are right, they germinate and produce an individual.
Unit 1
1. A. Most of the water is in a liquid state.
B. The Earth has moderate temperatures. 2. Inorganic biomolecules: water and minerals. Organic biomolecules: carbohydrates, proteins, nucleaic acids and lipids. 3. Autotrophic – nutrition – obtaining energy.
6. A – 2; B – 3; C – 1. 7. A. Bacteria are prokaryotic unicellular organisms.
B. Algae exhibit autotrophic nutrition, which means they photosynthesise. C. Moulds are unicellular fungi that grow in foods, such as fruit and bread.
Stimulus – interaction – effectors. Gamete – reproduction – sexual. 4. A. Eukaryotic; nucleus, plants; animals.
8. A. Monera; B. Protoctista; C. Protoctista; D. Protoctista.
B. DNA; prokaryotic, bacteria. 5. A. True. B. False. C. False. D. True.
9. A. Multicellular; B. Bacteria; C. Monera; D. Hypha.
6. The correct answer is C. 7. A. 1. Mitochondrion. 2. Plasma membrane. 3. Nucleus. 4. Vacuole. 5. Cell wall. 6. Chloroplast.
10. A. Bacteria; helpful.
B. Protozoa; harmful. C. Antibiotics; fungi.
B. Plant eukaryotic cell. It has a nucleus, a large vacuole, chloroplasts and a cell wall. Unit 3
8. A. Algae; autotrophic; photosynthesis. photosynthesis.
B. Division; budding. C. Unicellular; multicellular; systems.
1. The table must be completed in this way:
tissue;
organs;
9. The correct sequence of taxa is A. 10. The lynx belongs to the kingdom animalia, to the genus Lynx and and the species Lynx pardinus.
Plant Organs
Plant Functions
Stem
Keeps the plant erect and holds up the leaves.
Roots
Attach the plant to the ground and absorb the water and minerals the plant needs.
Leaves
Create the plant’s nutrients.
Flowers
Contain the reproductive reproductive organs of the plant.
Unit 2
1. Cocci; bacilli; vibrios; spirochaetes. spirochaetes. 2. Obtains nutrients by decomposing the remains of living beings.
2. A. Plants are autotrophic, since they produce their own nutrients through photosynthesis.
Parasite. Symbiotic – Obtains nutrients from other living beings and provides them with benefits.
B. Plants react to light, contact, temperature, humidity ... C. Plants reproduce sexually, through gametes.
3. A. False.
B. True. C. False. D. True. 4. 1. Spores are made in the gills.
2. Mycelia are generated from spores. 3. Mycelia develop a new mushroom. 5. Mycelium: the body of multicellular fungi.
Hypha: all of the filaments formed by the mycelium.
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3. 1. Water. 2. CO2. 4.Carbohydrates. 5. O2.
3.
Solar
energy.
4. It is completely false. Plants always need to respire. 5.
Tropisms are a type of response in which the plant grows towards the stimulus or away from it. Nastic movements are the rapid movements of some parts of the plant and they are usually reversible.
6. A. Gravitropism. B. Thigmotropism. C. Thigmotropism. Thigmotropism. D. Hydrotropism.
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Answer key
7. A. Spores are cells that fall to the ground, and when conditions are right, they germinate and produce an individual.
B. In sporangia. C. Reproduction through spores is a type of asexual reproduction. 8. A and C are false. 9. Group: Gymnosperms.
It has seeds that are not in a fruit. It is an evergreen. Its flowers are called cones, and there are female and male cones. 10. A. Mosses are attached to the ground by filaments called rhizoids.
B. The stem of a fern is underground and it is called a rhizome. Branching off of it are leaves called fronds. C. At some stage of their lives, mosses and ferns reproduce through spores, which are produced in structures called sporangia.
1. • Gastrovascular cavities are saclike structures with a single opening that serves both to take in food and to expel any undigested material. Food is digested inside the gastrovascular cavity and the cells in the wall of the cavity absorb nutrients. This type of digestive system is found in cnidarians and Platyhelminthes.
• Digestive tracts are long tubes with one opening for taking in food (the mouth) and another opening for expelling undigested food (the anus). There are simple digestive tracts, such as those of annelids, or more complex digestive tracts, such as those of vertebrates. 2. 1. Sponge (has no digestive system). 2. Jellyfish (has a gastrovascular cavity). 3. Worm 4. Horse. 3.
5. Echinoderms move by using a system of tubes filled with liquid (ambulacral system). When the tubes contract, they project extensions called ambulacral or tube feet, which they use to move. 6. Compound eyes: Light (photoreceptor). Taste: substances in the water and in food (chemoreceptor). Lateral line: Vibrations and movements in the water (mechanoreceptor). Balance: Body movement (mechanoreceptor). Touch: Pressure (mechanoreceptor). Hearing: Vibrations in the air and water (mechanoreceptor). Smell: Substances in the air (chemoreceptor). 7. A and B are false. 8. Budding takes place when an animal produces a small lump, called a bud, and it develops until it forms a new individual; while fragmentation consists of an animal dividing its body into various parts, each of which develops into a new individual. Budding always has a reproductive function. Fragmentation sometimes has a defence function, such as when a starfish loses its arm in order to escape from a predator. 9. A. Testicles C. Fertilisation
Unit 4
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4. A. Stimuli B. Responses.
and
ovaries;
B.
Zygote.
10. In direct development, an individual that is born is similar to the adult; they only differ in size; while in indirect development the individual born is different from the adult; it is called a larva. Animals with direct development are all mammals, birds, reptiles, etc. Animals with indirect development are amphibians, arthropods, etc. Unit 5
1. The text must be completed in this way: (1) heterotrophic, (2) omnivore, (3) locomotion organs and a muscular system, (4) sense organs, (5) cephalisation, (6) sexual, (7) males, (8) females, (9) viviparous, (10) oviparous, (11) ovoviviparous. 2. A–2; B–2; C–2; D–2; E–1; F–1; G–1.
A. Cell nutrition
Exchange surfaces
3. The odd one out is in group C. Ophiuroidea are not cnidarians. They are echinoderms.
B. Nutrition process in plants
Stomata, root hairs
4. A–2; B–2; C–1; D–2.
C. Digestion in animals D. Respiration in animals E. Circulation and excretion in animals
Gastrovascular cavity and digestive glands Gills, blowhole Heart, nephridium
5. The incorrect sentence is E, since the majority are aquatic, although the most well known is the earthworm and it is terrestrial. 6. 1. Ambulacral/tube feet, characteristic of echinoderms. 2. ‘Parrot’s beak’, characteristic of molluscs.
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Answer key
7. The word that is the odd one out is in group C. A prawn is an arthropod, not a mollusc.
7. A. Amphibians can be classified into two groups, which are called anurans and urodeles.
8. Sentences A and B are true. Sentence C is false, since arthropods have complex and specialised organs (sense organs, tracheas, etc.). Sentence D is false, since the caterpillars that hatch from arthropod eggs are different from the adults.
B. The group of reptiles with no legs is called ophidians. C. The ostrich belongs to the bird group called ratites, which have atrophied wings. D. Mammals received this name because females have mammary glands that produce milk.
9. 1–C; 2–A; 3–D; 4–B. 10. The text must be completed in this way: (1) radial, (2) skeleton made of plates, (3) ambulacral, (4) movement, (5) breathe, (6) hunt. Unit 6
1. They are aquatic and endothermic, and they have a lateral line, fins and gills. 2. Bony fish
Cartilaginous fish
Do they have an operculum?
Yes
No
Do they have a swim bladder?
Yes
No
Where is the mouth?
Front end
Ventral area
What are their scales like?
Flat and round
Thick and tooth like
What is their tail fin like?
Homocercal
Heterocercal
Give an example.
Trout
Shark
8. Aerodynamic body shape, forelimbs are wings, they have feathers and thin, hollow bones. 9. They have hair on their bodies, females have mammary glands that produce milk to feed their young and the majority are viviparous. 10. Tuna → fish group, bony fish Toad → amphibian, anuran Lynx → mammal, placental Rays → fish, cartilaginous fish Koala → mammal, marsupial Trout → fish, bony fish
Lizard → reptiles, saurians Unit 7
1. A and C are false 2. 22nd September. Autumn equinox.
21st June. Summer solstice in the northern hemisphere 22nd December. Winter solstice in the northern hemisphere. 21st March. Spring equinox.
3. 1–B; 2–D; 3–A; 4–C. 4. The order would be B, D, A and C. 5.
Birds
Reptiles
• Have feathers
• Have teeth
• Endothermic
• Pulmonary respiration
• Have wings
• Ectothermic
• Pulmonary respiration
• Have scales
• Have scales
• They lay eggs with shells
• Have air sacs • They lay eggs with shells
6. A. (F) Birds have an aerodynamic shape allowing them to fly.
B. (F) Mammals have different types of teeth. C. True. D. (F) Reptiles lay eggs with shells and do not go through metamorphosis.
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3.
Type of planet
Planets
Rocky planets
Mercury, Venus, Earth and Mars
Gas planets
Jupiter, Saturn, Uranus and Neptune.
4. 1–C; 2–D; 3–A and 4–B. 5. A. (1) electromagnet, (2) magnetic field; B. (1) atmosphere (2) air; C. Air. 6. The sentence is true, since an observer on Earth’s surface will never be able to see the other side of the Moon. Since the rotation period of the Moon coincides with its orbit period (27.3 days), we always see the same side of the moon.
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Answer key
7.
Celestial body
Rotation
Around the Sun. On its axis. It takes 24 h.
It takes 365 days, 6 hours and 9 minutes.
On its axis.
Around the Earth.
It takes 27.3 days
It takes 27.3 days.
Earth
Moon
C. Underground water. D. Surface water.
Orbit
8. A. New moon.
B. First quarter. C. Full moon. D. Third quarter. 9. High tide. This is when the sea reaches its highest point in the tide cycle.
Neap tide. It occurs when the Moon and the Sun are at a right angle to Earth. The gravitational pull of the Sun and the Moon on the Earth offset each other and the resulting tides have small oscillations. This happens when the Moon is in the waning or waxing phase. 10. It is a spherical celestial body, about 3 476 kilometres in diameter. It does not have an atmosphere, which makes it vulnerable to the impact of meteorites on its surface and its temperature ranges from 100 ºC to –150ºC. It rotates on its axis very slowly, taking 27.3 Earth days to complete a rotation; and its orbit round Earth also takes 27.3 days.
8. (1) water, (2) Earth, (3) atmosphere, (4)clouds, (5) precipitation, (6) rain, (7) snow, (8) constant, (9) water, (10) rivers , (11) surface, (12) closed, (13) water, (14) constant. 9. Some of the reasons that students must state are: Water reserves for consumption are limited to fresh water. Its distribution on the planet is irregular. Its level of contamination is growing, since we contaminate it at a faster rate than we can treat it. It is consumed in greater and greater amounts. 10. Microorganisms – Waste water; Oil slicks – Oil spills in the sea; Pesticides and compost – Come from agriculture; Chemical substances – Come from industry.
Unit 9
1. The Earth’s crust is the outermost layer of the geosphere. It is solid and very thin.
There are two types of crust: the continental crust, which is thicker, and the oceanic crust, which is thinner. 2. A. Mantle.
B. Outer core. C. Crust D. Inner core. 3. B, D, E, F.
Unit 8
4. 1. B and C are false. 2. A. Troposphere. B. Mesosphere. C. Stratosphere. 3. A. Ozonosphere B. Mesosphere. . s l a i r e t a m e l b a i p o c o t o h p d e s i r o h t u A . A . S , a y a n A o p u r G ©
Property
Definition
Streak colour
The colour of a mineral when it is ground up.
Exfoliation
How a mineral breaks along a flat surface.
Lustre
4. A. Regulates B. Filter
Hardness
The appearance of a mineral’s surface when it reflects light. How resistant the mineral is to being scratched.
C. (1) Oxygen, (2) Carbon dioxide 5. Hole in the ozone layer radiation passes through.
CFCs
Ultraviolet
Acid rain – Nitrogen oxides and sulphur mixed with water – Stone deterioration Increasing greenhouse effect – Carbon dioxide and water vapour – Global warming. 6. A–F; B–F; C–T; D–T; E–F. 7. A. Glaciers and polar caps.
B. Oceanic and sea waters.
5. A–T; B–F; C–T; D–F; E–T. 6. A. The properties that allow us to identify rocks are: the shape in which it appears in nature, its composition and its texture..
B. To obtain aluminium. 7. Rocks
are divided into Igneous – Sedimentary – Metamorphic that can be 37
Answer key
Volcanic Plutonic Non detrital Detrital Foliated Non foliated 8. Igneous rocks
7.
Metamorphic rocks
Sedimentary rocks
slate
basalt
marble
granite
clay conglomerate limestone
Biomes of cold zones
Polar desert, tundra and taiga
Biomes of temperate zones
Deciduous forest, Mediterranean forest and steppe
Biomes of warm zones
Desert, savannah and tropical forest
8. The correct answer is C. 9. The over-exploitation of species due to hunting, fishing or gathering; the destruction of ecosystems; and the introduction of invasive species. 10. The correct sentence is B.
9. A. limestone and clay
B. clay 10. Petroleum oil comes from the remains of marine animals. Oil is used to produce different fuels and other materials, such as tar, plastic, fertilisers ...
Unit 10
1. An ecosystem is made up of a group of living beings called a biocoenosis, the environment they live in, which is called the biotope and the interactions among them. 2. A. Plants lose a large amount of water through their leaves, which is why they are covered with an impermeable wax.
B. When the colder weather arrives, some animals migrate or hibernate. C. Photosynthetic organisms in aquatic environments live at shallow depths in order to receive more light. 3. A-4; B-1; C-2; D-3. 4. Species A
Species B
Parasitism or predation
+
-
Mutualism
+
+
Competition
-
-
Commensalism
+
0
5. Consumers are heterotrophic organisms that feed on producers or consumers.
Decomposers are heterotrophic organisms that feed on the waste (bodies or excrement) of the trophic levels. 6. 4, 3, 1 and 2. 38
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