One effect of the pesticide ddt upon birds is to inhibit the production of the enzyme carbonic anhydrase, which controls calcium metabolism. it is believed that this causes eggshells to be thinner and weaker than normal and makes the eggs more prone to breakage. an experiment was conducted where 16 sparrow hawks were fed a mixture of 3 ppm dieldrin and 15 ppm ddt (a combination often found in contaminated prey). the first egg laid by each bird was measured, and the mean shell thickness was found to be 0.19 mm. a "normal" eggshell has a mean thickness of 0.2 mm. the null and alternative hypotheses are

Answer:

The null hypothesis: the mean egg thickness is 0.2 mm

The alternative hypothesis: the mean egg thickness is less than 0.2 mm

In statistics, the null hypothesis states that there is no significant difference between the observed value and the mean thickness. The alternative hypothesis states is the opposite and states the scientist's "idea" behind the experiment. Here, it refers to the fact that due to DDT, the egg shell will be thinner compared to the mean value.

b tumor cells have a cell wall instead of a membrane

explanation:

tumor cells different from normal cells because tumor cells have a cell wall instead of a membrane.