Can you imagine astronauts' everyday life in space? They also need to eat,  sleep, exercise and relax. They do the same things as us, but they do them differently.
   On Earth, we put food on a plate. Gravity holds the food down and keeps it on a place. But there is almost no gravity in space, so food can float （漂浮）away, and astronauts must eat carefully.
   Sleeping is very different in space. Some astronauts like to float in the air, but most like to be in a sleeping bag. They tie the bag to a wall so that they won't float away at night.
   Exercise is very important in space. On Earth,  your legs carry your body,  but in space, astronauts float, so they do not use their legs often. This is very bad for their legs, so they must exercise for thirty minutes every day.
   After a day's work, astronauts relax. They may listen to music, read, watch films, play games, or talk to their friends and families on the radio. Sometimes they just enjoy floating in the air.

科研人员将T﹣DNA片段（T﹣DNA的区段带有潮霉素抗性基因）插入正常株（野生型）水稻愈伤组织单个染色体DNA中，导致被插入基因（PIN蛋白基因）发生突变，得到矮杆水稻（突变型）Q．科研人员利用矮杆突变体Q进行自交得到F₁：

（1）统计F₁代植株的株高，并剪取其叶片在含____ 选择培养基进行筛选，统计实验结果如表．

据表分析，说明矮杆突变体性状是____ 性性状，水稻的株高是由____ 对等位基因控制的，判断依据是____ ．

F₁矮杆植株自交得到F₂，F₂中矮杆性状所占比例为____ ．

（2）已有研究表明PIN蛋白与生长素的极性运输有关．研究者据此推测T﹣DNA片段的插入导致____ （选“矮杆水稻”或“正常水稻”）PIN蛋白基因的表达量____ ，从而造成生长素的极性运输水平下降，植株中出现矮杆性状．

（3）为验证上述推测，研究者首先需要从水稻叶片中提取总RNA，经____ 过程获得cDNA；

再根据PIN蛋白合成基因的____ 设计引物，定量扩增PIN蛋白合成基因，得出样品中PIN蛋白合成基因转录出的mRNA总量；最终比较PIN蛋白基因在正常水稻和矮杆水稻细胞内的表达量．

（4）为证明“PIN蛋白定位于植物细胞膜上”，研究者实验设计的核心步骤及预期实验结果是____ （填字母）．

a．PIN基因与绿色荧光蛋白基因融合与质粒构建重组DNA

b．已知细胞膜蛋白基因与红色荧光蛋白基因融合构建重组DNA

c．用显微镜观察，细胞膜上仅出现红色荧光

d．用显微镜观察，细胞膜上仅出现绿色荧光

e．用显微镜观察，细胞膜上出现红色和绿色荧光．