Which Cisco Catalyst switches fit in the access area？（） [" Cisco Catalyst 2900 Series，Catalyst 7300 Series，and Catalyst 8000 Series"," Cisco Catalyst 2900 Series，Catalyst 3700 Series，and Catalyst Series"," Cisco Catalyst 2700 Series，Catalyst 7300 Series，and Catalyst 8000 Series"," Cisco Catalyst 2700 Series，Catalyst 3700 Series，and Catalyst4500 Serie"]
Construction of a new automobile parts manufacturing facility has recently been completed. Thefacility IT manager wants to deploy voice over WLAN. During your initial walkthrough， you observenumerous highly reflective surfaces on the manufacturing equipment and in the buildingconstruction itself. What potential problem exists that should be accounted for during your sitesurvey？（） ["LOS modulation","Multipath distortion","RF signal absorption","RF signal attenuation","Fresnel zone impedance"]
下列各项中属于变动成本的有（）。 ["直接材料","直接人工","直线法计提的折旧费","产量法计提的折旧费","电话费"]
定位销用于工件圆孔定位，其中，短圆柱销限制（）个自由度。 ["6","2","4","8"]
情绪应对的方式对于应对由不可控的压力源产生的影响更为有效。
简述恒温在动物进化史上的意义？
