The first species to live on new land, such as that formed from volcanic lava, are called A: clomax community. B: keystone species. C: foundation species. D: pioneer species. E: parasite.
The first species to live on new land, such as that formed from volcanic lava, are called A: clomax community. B: keystone species. C: foundation species. D: pioneer species. E: parasite.
18 未知类型：{'options': ["It's the cradle of civilization.", 'There are many kinds of birds.', 'There is plenty of species.', 'There are various species of fish.'], 'type': 102}
18 未知类型：{'options': ["It's the cradle of civilization.", 'There are many kinds of birds.', 'There is plenty of species.', 'There are various species of fish.'], 'type': 102}
Effects of long term use of pesticides include ( ) A: imbalances in ecosystems B: develop new dominant pest species C: lose keystone species. D: Beneficial organisms and even natural enemies of the pests may be among the species eliminated by pesticides
Effects of long term use of pesticides include ( ) A: imbalances in ecosystems B: develop new dominant pest species C: lose keystone species. D: Beneficial organisms and even natural enemies of the pests may be among the species eliminated by pesticides
A<br/>given isotype of antibody is() A: A heavy chain variant encoded by allelic genes B: Genetic marker in different individuals within the species C: Present in all normal individuals in the same species. D: Epitopes located at the hypervariable region. E: Recognized by anti-idiotype antibody.
A<br/>given isotype of antibody is() A: A heavy chain variant encoded by allelic genes B: Genetic marker in different individuals within the species C: Present in all normal individuals in the same species. D: Epitopes located at the hypervariable region. E: Recognized by anti-idiotype antibody.
The representative strain that can represent the typical characteristics of a strain is called ( ). A: Model species B: Typical species C: Representative species D: Reference species
The representative strain that can represent the typical characteristics of a strain is called ( ). A: Model species B: Typical species C: Representative species D: Reference species
Over the last century, paleontologists have used small differences between fossil specimens to classify Triceratops into sixteen species. This classification is unjustified, however, since the specimens used to distinguish eleven of the species come from animals that lived in the same area at the same time. Which of the following, if true, would enable the conclusion of the argument to be properly drawn A: Not every species that lived in a given area is preserved as a fossil. B: At least one individual of every true species of Triceratops has been discovered as a fossil specimen. C: No geographical area ever supports more than three similar species at the same time. D: In many species, individuals display quite marked variation. E: (E) Differences between fossil specimens of Triceratops that came from the same area are no less distinctive than differences between specimens that came from different areas.
Over the last century, paleontologists have used small differences between fossil specimens to classify Triceratops into sixteen species. This classification is unjustified, however, since the specimens used to distinguish eleven of the species come from animals that lived in the same area at the same time. Which of the following, if true, would enable the conclusion of the argument to be properly drawn A: Not every species that lived in a given area is preserved as a fossil. B: At least one individual of every true species of Triceratops has been discovered as a fossil specimen. C: No geographical area ever supports more than three similar species at the same time. D: In many species, individuals display quite marked variation. E: (E) Differences between fossil specimens of Triceratops that came from the same area are no less distinctive than differences between specimens that came from different areas.
Clearcutting benefits the regeneration of ____ tree species.
Clearcutting benefits the regeneration of ____ tree species.
How many_______known altogether A: species of fishes are B: species of fish is C: specieses of fish are D: species of fish are
How many_______known altogether A: species of fishes are B: species of fish is C: specieses of fish are D: species of fish are
Shelterwood cut favors the regeneration of _______tree species.
Shelterwood cut favors the regeneration of _______tree species.
1-2 题，第一篇新闻听力 1 choose the right answer A: Many<br/>people have been attacked by Devil Firefish. B: The<br/>Mediterranean is a natural habitat of Devil Firefish. C: Invasive<br/>species are driving away certain native species. D: A deadly fish has been spotted in the Mediterranean waters.
1-2 题，第一篇新闻听力 1 choose the right answer A: Many<br/>people have been attacked by Devil Firefish. B: The<br/>Mediterranean is a natural habitat of Devil Firefish. C: Invasive<br/>species are driving away certain native species. D: A deadly fish has been spotted in the Mediterranean waters.