Phototropism is reaction of a plant to a light stimulus. Growth of the plant or its part grow towards the light stimulus is called positive phototropism. Growth of the plant or its part away from the light stimulus is called negative phototropism. Since, the plant grows away from the sunlight (away from the light stimulus), it is negatively phototropic.
Gravitropism is reaction of a plant to gravity. Growth of the plant or its part in the same direction as gravity is called positive gravitropism. Growth of the plant or its part grow in the opposite direction of gravity is called negative gravitropism. The root is positively gravitropic (grows deeply straight down into the ground, in the same direction as gravity).
b. Remora fish attaching themselves to sharks
c. Birds feeding on insects stirred up by grazing animals
d. Birds eating scraps of food from a crocodile’s teeth
Answer:
The correct answer would be a. Tapeworms living in a mammal’s intestinal tract.
Parasitism refers to the relationship between two organisms or species in which one organism lives in or on the body of the other.
The organism which lives on the body of the other is termed as the parasite while the other organism is termed as the host.
The parasites derive their nutrition from the host but they do not kill their host at once.
Examples may include tapeworm, hookworm, Plasmodium,flukes, fleas et cetera.
The tapeworm are the flat segmented flatworm that live as parasite in the intestine of the mammals. They derive their nutrition from the partly digested food of the host. It deprived the host of nutrients.
Answer:
A scientist would ask a different question when he or she founds that the observed results are different from the expected results.
Explanation:
When one expects something and gets something else, then one is having a big enough cause to ask for new questions and initiate a new investigation. Scientific investigation is the process by which the researchers and scientists use a planned approach to answer questions regarding the world around us.
Answer:
B. viral reverse transcriptase to make a DNA copy that is integrated into the host genome and then host RNA polymerase transcribes it.
Explanation:
RNA retrovirus when enters into its host cell it first use its reverse transcriptase enzyme and converts its RNA genome into the DNA so that viral DNA can be incorporated into the host cell and it can be replicated with the host cell.
One of the famous example of RNA retrovirus is HIV which infect CD4 cells and converts its RNA into cDNA with the help of reverse transcriptase enzyme and then this DNA enters the nucleus of the cell and incorporates into the host genome. Then it use host machinery to be transcribed. So the correct answer is B.