Correct Answer: B) synthesis and secretion of proteins

Explanation

The question is asking what the presence of extensive amounts of rough endoplasmic reticulum in a cell indicates. The options are: A) synthesis and metabolism of CH₂O₃ , B) synthesis and secretion of proteins (correct), C) synthesis of ATP, and D) contraction. The rough endoplasmic reticulum (RER) is a type of organelle found in eukaryotic cells. It is called rough because it has ribosomes attached to its surface, which gives it a bumpy appearance under a microscope. The ribosomes on the RER are responsible for synthesizing proteins. Therefore, if a cell has extensive amounts of RER, it is an indication that the cell is involved in the synthesis and secretion of proteins, which is option B and is the correct answer. Proteins have many important functions in the cell, including structural support, enzymatic activity, and cell signaling. Some proteins are also secreted from the cell and used by other cells or tissues in the body. Therefore, cells that need to produce large amounts of proteins, such as cells in the pancreas that produce insulin, have extensive amounts of RER. To summarize, the presence of extensive amounts of rough endoplasmic reticulum in a cell indicates that the cell is involved in the synthesis and secretion of proteins, which is option B and is the correct answer.

Correct Answer: D. harvested plants in a unit area

Correct Answer: C. rhizomes

Correct Answer: D) Thymine

Explanation

RNA (Ribonucleic acid) is a type of genetic material that plays an important role in protein synthesis in cells. It is made up of nucleotides, which are the building blocks of RNA. Each nucleotide contains a sugar, a phosphate group and a nitrogenous base. The four nitrogenous bases found in RNA are Adenine (A), Guanine (G), Cytosine (C) and Uracil (U). The question is asking which of the nitrogenous bases is not present in RNA. The correct answer is option D, Thymine (T). Thymine is only found in DNA (Deoxyribonucleic acid), which is another type of genetic material found in cells. RNA uses Uracil instead of Thymine. Therefore, the correct answer to the question is option D, Thymine. It is important to note that Adenine, Guanine and Cytosine are present in both DNA and RNA, while Thymine is only found in DNA.

Correct Answer: C) larger and fewer along the food chain

Explanation

In a predator food chain, there are different levels of consumers. The secondary consumers eat the primary consumers, while the tertiary consumers eat the secondary consumers. The question is asking what happens to the organisms as we move up the food chain from secondary to tertiary consumers. Option A suggests that the organisms become smaller as we move up the food chain, but this is not correct. In fact, the organisms usually become larger as we move up the food chain. Option B suggests that the number of organisms stays the same along the food chain. This is also not correct, as the number of organisms usually decreases as we move up the food chain. Option C is the correct answer. This option suggests that the organisms become larger and fewer along the food chain. This is because as we move up the food chain, each organism needs to consume more prey to get the energy it needs. This means that there are fewer organisms at each level, but they are usually larger. Option D suggests that the organisms become parasitized along the food chain as consumers get bigger. This is not correct, as parasitism is not directly related to the size of the consumer. Option E suggests that there is a change in the distribution of the organisms along the food chain, but this is not related to the question. In summary, the correct answer is Option C, which states that the organisms become larger and fewer along the food chain. To understand more about food chains and how organisms interact with each other, you can read relevant sections of your Biology textbooks

Correct Answer: D. they do not cause disease

Correct Answer: B. Diaphragm contracts and becomes dome shaped

Correct Answer: D) its body absorbs digested food

Explanation

A tapeworm is a type of parasite that lives in the intestines of animals, including humans. The question is asking why a tapeworm does not have an alimentary canal. The alimentary canal is the tube-like structure that runs through the body and is responsible for processing food. The options provided are: it is antotropic, it does not feed, it has no enzymes, its body absorbs digested food, or it is long. The correct answer is option D, which states that the tapeworm's body absorbs digested food. Unlike other animals, a tapeworm does not have a mouth or a digestive system. Instead, it absorbs nutrients through its skin-like outer layer directly from the digestive system of the host animal. The host animal's digestive system breaks down the food into nutrients which are then absorbed by the tapeworm's body. This adaptation allows the tapeworm to survive in its host without having to expend energy on digestion. Rather, the tapeworm can focus all of its energy on reproduction and growth. While this may seem like an advantage for the tapeworm, it can be detrimental to the host animal's health, as the tapeworm can steal nutrients that the host animal needs to survive. In summary, a tapeworm does not have an alimentary canal because it absorbs nutrients directly from the host animal's digestive system, allowing it to focus all of its energy on reproduction and growth.

Correct Answer: D) water molecules from a dilute solution to a concentrated solution through a semi permeable membrane

Explanation

Osmosis refers to the movement of water molecules from a region of high concentration to a region of low concentration across a semi-permeable membrane. This process is passive and does not require energy. The question is asking us to identify the correct definition of osmosis from the given options. Option A is incorrect because osmosis is specifically the diffusion of water molecules, not atoms and molecules in general. Option B is correct because it describes the movement of water molecules from a dilute solution to a concentrated solution across a semi-permeable membrane. Option C is incorrect because it describes the process of diffusion, not osmosis. Option E is also incorrect because it does not relate to the movement of water molecules across a semi-permeable membrane. Therefore, the correct answer to this question is Option D, which correctly describes the movement of water molecules from a dilute solution to a concentrated solution through a semi-permeable membrane.

Correct Answer: C. conducting census