The common component of air pollution is particulate matter (PM). This is a complex mixture of extremely small particles and liquid droplets.
The major components of PM are sulphates, nitrates, ammonia, sodium chloride, black carbon, dust particles and water. PM comes from dust , soot, smoke, industry and vehicle exhaust as well as complex chemical reactions with other pollutants.
Burning of fossil fuels produces sulphur dioxide . It is a colorless gas that pollutes the air and can cause health problems affecting the respiratory system.
Answer:
<u>C) They may provide selective advantages.
</u>
<u>D) Slight differences in the genetic code may have significant results.</u>
Explanation:
The genetic code is universal, and present in most living beings . Generally, in most living organisms, the same codons are assigned to the same amino acids.
DNA sequences make up genes that may have multiple variants, called alleles. DNA deoxyribonucleic acid, is transcribed into mRNA and then translated into amino acids that form proteins.
Natural selection mainly acts on phenotypes, which are dependent on proteins and the organisms's environment. Phenotypes conferring advantageous traits are favored by the selection process- these help groups of organisms evolve over time.
Answer:
(A)Yes.
Explanation:
Homologous structures provide evidence for common ancestry.
Good Luck
<span>The structure of the feet and legs varies greatly among frog species, depending in part on whether they live primarily on the ground, in water, in trees or in burrows. Frogs must be able to move quickly through their environment to catch prey and escape predators, and numerous adaptations help them to do so. Most frogs are either proficient at jumping or are descended from ancestors that were, with much of the musculoskeletal morphology modified for this purpose. The tibia, fibula, and tarsals have been fused into a single, strong bone, as have the radius and ulna in the fore limbs (which must absorb the impact on landing). The metatarsals have become elongated to add to the leg length and allow the frog to push against the ground for a longer period on take-off. The illium has elongated and formed a mobile joint with the sacrum which, in specialist jumpers such as ranids and hylids, functions as an additional limb joint to further power the leaps. The tail vertebrae have fused into a urostyle which is retracted inside the pelvis. This enables the force to be transferred from the legs to the body during a leap </span>
<span>The muscular system has been similarly modified. The hind limbs of ancestral frogs presumably contained pairs of muscles which would act in opposition (one muscle to flex the knee, a different muscle to extend it), as is seen in most other limbed animals. However, in modern frogs, almost all muscles have been modified to contribute to the action of jumping, with only a few small muscles remaining to bring the limb back to the starting position and maintain posture. The muscles have also been greatly enlarged, with the main leg muscles accounting for over 17% of the total mass of the frog.</span>
Activation energy is required to start a chemical reaction. Activation energy is the energy needed to allow the reactant to react. Activation energy is measured in Joules (J).
