ncert solutions for class 7 social science geography chapter 5
what are tides and how are they caused?
the rhythmic rise and fall of ocean water twice a day is called a tide. tides are caused due to the gravitational pull exerted by the sun and the moon on the earth’s surface.
describe a river. i neeeed help aswell 17 questions connexus 7th grade challenges facing northern eurasia quiz
100% correct 
1. d
2. b
3. islam then eastern orthodox church
4. a
5. a
6. b
7. shrinkage of the arial sea solution: there are five common features in stanza 2. these features are the sun, the air, the water, peaceful harvest, hands and the labour. directions: find the relation between the first pair of words given below and select the word from the given options that bears the same relationship with the other word given in the set:breeze : cyclone : : drizzle : ? five factors are known to affect allele frequency in populations i.e., hardy-weinberg equilibrium. these are gene migration or gene flow, genetic drift, mutation, genetic recombination and natural selection.gene migration or gene flow – it is movement of alleles into a gene pool or out of a gene pool. when this movement of alleles takes place gene frequencies change in the original as well as in the new population. new genes/alleles are added to the new population and these are lost from the old population. this will lead to a gene flow if this gene migration, happens multiple times.genetic drift – if the movement of alleles into a gene pool or out of a gene pool takes place by chance it is called genetic drift. this always influences frequencies of alleles and s inversely proportional to the size of the population. it sometimes result into founder effect i.e., when a small group of individuals get isolated from a larger population to form a new population. genetic drift may result into reduced genetic variation.mutation – is the large difference arising suddenly in a population, they are random and occur in all directions.natural selection – is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny. that is nature selects only those traits which help an organism to survive in the changed conditions. those that are not fit for survival perish in the long run leading to evolution of new species.genetic recombination – production of new offspring with traits which differ from parents is called genetic recombination. sylvia frank chlh 274 homework problems chapter 3 1. a. crude death rate: total populace death in a specific span-time at the mean year. b. age-specific rate: total incidence occurred in a specific-age group of the populace in a specific span time. c. cause-specific rate: total death of a populace from a specific-cause in a specific span-time at the mean year. d. proportional mortality ratio: total death within a populace due to a specific-cause divided by the total death in the populace e. maternal mortality rate: incidence of death because of birth of a child or due to pregnancy associated complications. f. infant mortality rate: rate of event of newborn death over a year by birth of newborn over a same interval. g. neonatal mortality answer: k=7 i have determined the cause and a fix will be in the next version. we are asked to complete the sentence. [readmore]a law reliably predicts the behavior of matter, while a theory provides an explanation for that behavior.