The correct answer is "C".
Onion cell is a plant cell and human cheek cell is an animal cell. Hence, onion cell has a cell wall<span> but not in human cheek cells because animal cells do not have cell wall. Both cells have single nucleus. Since, human cheek cell is an animal cell, chloroplasts are cannot be seen in the human cheek cells.</span>
Answer:
Viruses are like hijackers. They invade living, normal cells and use those cells to multiply and produce other viruses like themselves. This can kill, damage, or change the cells and make you sick. Different viruses attack certain cells in your body such as your liver, respiratory system, or blood.
Explanation:
Viruses tend to target specific tissues (cells) in the host.
For example, the influenza virus has a predilection for the respiratory tract, hepatitis viruses target the liver, polio virus targets the motor neurons of the spinal cord and rotavirus multiplies in the gut. Symptoms of a viral infection may be subtle and nonspecific or specific and suggestive of the causative agent.
Dengue virus, Ross river virus, measles and rubella infections are associated with fever and a widespread red rash, chicken pox and herpes simplex viruses are associated with blistering, often localized, rashes; and hepatitis viruses cause liver damage and jaundice.
Bacteria tend to be less tissue-specific and non-discriminatory than viruses and can cause a variety of infections once they have invaded the host.
These bacterial infections are often manifested by the presence of pus wherever the bacteria settle, and systemic symptoms such as fevers, chills, pain, swelling and loss of function occur when bacteria invade and multiply.
During the second gap, or G2 phase, the cell continues to grow in size and produce proteins necessary for cell division. Microtubules, filamentous internal structures, necessary for separating the chromosome copies are made during this phase. The second internal checkpoint that determines if the cell can continue through its cycle occurs in G2. While the G1 checkpoint checks to verify DNA is error free before replication, the checkpoint in G2 confirms the new DNA is error free after replication
Answer:
339
Explanation:
the FCI recognizes 339 breeds of dogs which are divided into 10 groups based on the dog’s purpose or function or on its appearance or size. The 10 groups are:
Sheepdogs and Cattle Dogs, other than Swiss Cattle Dogs (this group includes most of the dogs found classified as "herding dogs" by other kennel clubs).
Pinscher and Schnauzer, Molossoid Breeds, Swiss Mountain and Cattle Dogs and Other Breeds (the Molossian breeds include the dogs known as the mastiffs by most other kennel clubs)
Terriers
Dachshunds
Spitz and Primitive Types
Scent hounds and Related Breeds
Pointers and Setters
Retrievers, Flushing Dogs, Water Dogs
Companion and Toy Dogs
Sighthounds
Answer:
1. interactions
2. environment
3. sun
4. photosynthesis
5. chemical
6. producers
7. food
8. energy
9. organisms
10. herbivores
10. first
12. Heterotrophs
13. second
Explanation:
An ecosystem consists of a community of living organisms
interacting with each other and the environment. The source of energy that fuels most ecosystems is the sun. Plants use the Sun’s energy to produce food in a process called photosynthesis.
Organisms that use energy from the Sun or energy stored in chemical compounds to produce their own nutrients are called autotrophs. They are also called producers because most other organisms depend on autotrophs for food and energy. Heterotrophic organisms that can’t make their own food may obtain nutrients by eating other organisms. A heterotroph that feeds only on plants is called an herbivore. Herbivores are also called first order heterotrophs. Heterotrophs that feed on other herbivores are second order heterotrophs.