1. Answer: A
Explanation: For a cell to form proteins, the specific types of proteins are coded for by the genes in DNA (found in the chromosomes of the nucleus). To produce proteins, the genes are first transcribed by RNA polymerase to form messenger-RNA. The mRNA is then translated into proteins by ribosomes in the cytoplasm of the cell.
2. Answer: B
Explanation: Translation of genes into proteins is dependent on the sequence of nucleotides. They are translated in sequences of 3 nucleotides known as codons. Therefore adding a nucleotide on a piece of DNA causes what is referred to as a frame-shift mutation. The 3 sequences (of codons) is interrupted and shifted by one nucleotide. Therefore, the codons change and the amino acids translated will also change.
3. Answer: A
Expanation: Producers are significant in a food chain because they incorporate the energy of the sun into the food chain. This is why they are at the base of the food chain and have the largest biomass. They are consumed by primary consumers which are consumed by secondary consumers which are consumed by tertiary consumers and so on.
4. Answer: D
Explanation: Plants are consumed by herbivores. Therefore, a decrease in plant population due to drought was resulted to decrease in herbivore population. This is due to stiff competition by the herbivores for the scarce plant population. Carnivores consume herbivores. Due to a decrease in the herbivore population, then the carnivore population would also decrease.
5. Answer: A
Explanation: Burning of fossil fuels emits carbon dioxide gas which is a greenhouse gas. Greenhouse gas traps infrared wavelength of lights hence warming up the atmosphere, causing global warming. Reduction in use of fossil fuels will hence alleviate an increase in global temperature hence protect coral in the oceans from bleaching.
Explanation:
When the barge enters the northern most part of the river, the southward current is 0.67 m/s. How will the barge be affected? The barge will move slower. The direction of the barge will change.
Systemic circuit is defined as one of the two circuit of circulation that occurs in human body.
<h3><u>Explanation</u>:</h3>
The circulatory system is divided into two phases in the human body. They are:
A. Pulmonary circulation
B. Systemic circulation.
The pulmonary circulation is the short circuit of circulation that starts from the right ventricle, goes to lungs via pulmonary artery and returns to left auricle via pulmonary vein.
The systemic circulation is the bigger circuit that starts from the left ventricle, goes to each and every organ of the body via aorta, and returns to the right auricle via venacava.
Answer:
2 Major Subdivisions:
Central Nervous System
Peripheral Nervous System
Explanation:
The central nervous system (CNS) regulates the majority of bodily and mental activities. It is divided into two parts: the brain and the spinal cord. The brain is the core of our ideas, the translator of our surroundings, and the source of control over physical action.
The PNS is the nerve that links the CNS to the rest of the body. The peripheral nervous system's principal job is to link the brain and spinal cord to the rest of the body and the outside world. The peripheral nervous system sends and receives information to and from the central nervous system. This is done by neurons that convey information from sensory receptors in the eyes, ears, skin, nose, and tongue, as well as stretch receptors and nociceptors in muscles, glands, and other internal organs.
Answer: These may be:
- physical defenses (1st line)
- chemical defenses (2nd line)
Explanation:
Plants employ several methods in order to defend themselves from pathogens. These may be physical defenses or chemical ones. Several have adaptations to their surfaces that prevent the entry of pathogens, called physical barriers such as
- thick waxy cuticles
- thorns, which are modified plant branches
- spines, which are modified plant leaves
- gall production at infected sites to prevent pathogenic spread
Chemical defenses include the production or secretion of:
- defensins
- antimicrobials such as tannins or resins
- gum at areas facing pathogenic attacks