Need assistance on these few questions in which i'm a little stuck on.
1. Which hypothesis is considered a likely explanation for the events of the Cambrian explosion?
A) Complex predator-prey relationships and increased atmospheric oxygen levels promoted animal diversification.
B) A great surge of volcanic activity was triggered by significant movements of the continental plates and possibly by an asteroid impact.
C) Solar flares led to increased UV radiation intensity, which in turn promoted a high rate of mutation. This led to rapid diversification of animals.
D) The massive growth of swamp vegetation depleted the atmosphere's carbon dioxide and eventually cooled the Earth's climate.
2. Light skin is most adaptive in northern latitudes because
A) dark skin allows folate destruction when UV radiation is less.
B) the greater UV radiation in northern latitudes destroys vitamin D.
C) increased melanin causes an increase in the risk of melanoma.
D) light skin in northern latitudes allows adequate folate for fetal development.
3. The human papillomavirus (HPV) causes many cases of cervical cancer and oropharyngeal cancer. There is a vaccine that protects against the strain that causes cervical cancer, but it is not certain that same vaccine protects against oropharyngeal cancers. What experiments could medical professionals perform to best determine the effectiveness against oropharyngeal cancers?
A) Randomly assign a number of young adults to either a group to be vaccinated or a non-vaccinated group and record the incidence of cervical or oropharyngeal cancers in each.
B) Compare the incidence of cervical and oropharyngeal cancers in people who have been vaccinated and those who chose not to be vaccinated.
C) Vaccinate many people and compare the incidence of cervical cancers to the incidence of oropharyngeal cancers.
D) Compare the incidence of cervical cancers and oropharyngeal cancers in the general population.
4. The calcium that triggers muscle contraction is stored in the
A) motor neuron.
B) plasma membrane of cells.
C) endoplasmic reticulum.
D) mitochondria.
Any help is appreciated, thanks!
