Biology Test 344

While morphological features, reproductive features, and genetic similarities are crucial for classifying organisms into families, geographic distribution is not a primary criterion for this level of classification. Taxonomy focuses on the physical, genetic, and reproductive characteristics to determine relationships among organisms.

The term survival of the fittest was used by Herbert Spencer. "Survival of the fittest" is a phrase that originated in evolutionary theory as a method to describe the mechanism of natural selection. Herbert Spencer first used the phrase - after reading Charles Darwin's On the Origin of Species - in his Principles of Biology (1864), in which he drew parallels between his own economic theories and Darwin's biological ones, writing.

Cats and dogs belong to the order Carnivora, which includes animals that have primarily carnivorous diets. Cats are part of the family Felidae, while dogs belong to the family Canidae. This classification reflects their dietary habits and physical characteristics common among carnivores.

The family is the taxonomic rank that groups together multiple genera with similar characteristics. For example, the family Felidae includes the genus Panthera, which contains lions and tigers, among others. Families are characterized by shared features among the included genera, indicating a close evolutionary relationship.

Budding is an asexual mode of reproduction in Hydra and sponges. Bud is formed as an outgrowth on the body surface, then detached to form new animal.

Viruses are characterized by a protein coat, known as a capsid, which encloses their genetic material. This coat protects the viral genetic material and helps in attaching the virus to host cells. Viruses do not have a cellular structure, contain either DNA or RNA (but not both), and cannot replicate without infecting a host cell, making Option D the correct answer.

Axon is a long fibre which transmits impulses away from the cell body.

Mycorrhiza refers to a symbiotic association between fungi and the roots of a plant. In this relationship, the fungus enhances the plant's nutrient and water absorption capabilities, while the plant provides the fungus with carbohydrates produced through photosynthesis. This mutually beneficial relationship is crucial for the health of many ecosystems, making Option C the correct answer.

Archaebacteria are believed to have originated at a time when there were extreme conditions in the biosphere. Even today they are found in environments where other kinds of bacteria cannot survive. So they are considered to be the oldest of the living fossils, e.g., Methanobacterium, Methanococcus, etc.

All of them are not halophiles. Only some forms like Halobacterium, Halococcus can survive under extreme saline conditions. All of them are not fossils because many forms are still surviving and flourishing.

Blood is considered a connective tissue because it connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing wastes. It has a liquid extracellular matrix called plasma and is unique among connective tissues for being fluid. An interesting fact about blood is that it can be considered a transport system for the body, carrying cells and antibodies that protect the body from infection.